From: gazissax@netcom.com Newsgroups: misc.kids.info,misc.answers,news.answers Subject: misc.kids FAQ on Childhood Vaccinations, Part 2/4 Followup-To: misc.kids.health Approved: news-answers-request@MIT.EDU, kids-info-request@ai.mit.edu Reply-To: gazissax@netcom.com Summary: This FAQ contains information on vaccinations, with particular focus on the vaccinations given to children. Section 2 contains information about the vaccines which are on the required vaccination schedule within the USA. Archive-name: misc-kids/vaccinations/part2 Posting-Frequency: monthly Last-Modified: October 23, 1999===============================================================================
Q3a.1 What is diptheria, and what are the risks of the disease?
Diptheria is a contagious disease affecting the nose, throat, and
skin. Complications include paralysis (about 20% of patients) and
heart damage (about 50%) (Pantell, Fries, and Vickery). The Merck
manual has a very long list of complications, mostly involving the
heart, and says that complications are likely if antitoxin isn't
administered properly. The death rate was 35% before antitoxin was
available, and is now 10% (Harrison).
Q3a.2 How common was diptheria before routine vaccination, and how
common is it now?
In 1900, there were 40.3 deaths per 100,000 population from diptheria
in the US. There was a sharp decline in the number of deaths per 100,000
both before and after routine vaccination was instituted in the 1940s, and
in 1990 there were 4 cases of diptheria reported in the US. (_Historical
Statistics of the United States, Colonial Times to 1970_ and _Statistical
Abstracts of the United States_.
In Europe, there were large diptheria epidemics during and after World
War II, with an estimated one million cases and 50 000 deaths in 1943
(source: WHO web page on diptheria, written March 1998,
http://www.who.org/gpv-dvacc/diseases/diphtheria_dis.htm). More
recently, there have been large epidemics in Russia and the Newly
Independent States.
Q3a.3 How effective is the diptheria vaccine?
"The fatality rate in immunized populations is one-tenth that in the
unimmunized population. Paralysis is 5 times and 'malignant' disease
15 times less common in immune than in nonimmune individuals."
(Harrison)
Q3a.4 How long does the diptheria vaccine last?
Ten years.
Q3a.5 What is pertussis, and what are the risks of the disease?
Pertussis, or whooping cough, is a very contagious disease of the
respiratory tract. Its attack rate in unvaccinated household contacts
is over 90% (PDR) or up to 90 and in some cases 100% (Harrison).
Pertussis is very serious in children under 2, with a mortality rate
on about 1 to 2%. (Merck) "Prior to the availability of a vaccine,
pertussis caused as many deaths as all other contagious disease
_combined_." (Harrison, p. 607) Complications include various lung
complications (The Merck Manual has a long list of these), cerebral
complications, hemorrage into the brain, eyes, skin, and mucuous
membranes. In addition to killing, it can leave surviving infants
with lasting lung damage and neurological diseases.
The mortality rate is higher in developing countries, partly because
children in these countries contract pertussis at a younger age (and
mortality is higher at younger ages), and partly due to an association
with protein-energy malnutrition (Galazka). This same article estimated
that in the industrialized world, 0.04% of infected children die from
pertussis and complications, usually pneumonia "Among vaccine-preventable
diseases, pertussis rivals measles and neonatal tentanus in importance
and severity in young children in developing countries and is third only
to measles and neonatal tetanus as a cause of death. It is estimated
that pertussis is still causing some 340,000 deaths of children in the
world each year." (Galazka)
Q3a.6 How common was pertussis before routine vaccination, and how
common is it now?
[Note: This section may be outdated, since the introduction of the
new acellular vaccine has caused changed in vaccination schedules and
vaccination coverage. More recent information on international vaccine
schedules and disease incidence may be found at http://www.who.org.)
"Since immunization against pertussis (whooping cough) became
widespread, the number of reported cases and associated mortality
declined from about 120,000 cases and 1,100 deaths in 1950, to an
annual rate of about 3,500 cases and 10 fatalities in recent years."
(PDR) For unknown reasons, there has been an increase in the US recently.
"Over 6000 cases of pertussis were reported in the U.S. in 1993, the
highest number in 25 years." (N Engl J Med 1994 Jul 7; 331:16-21,
summarized in Journal Watch for July 22, 1994.) There is also a
recent report (MMWR Nov 11, p. 807) of a strain of pertussis
resistant to erythromycin.
In some other countries, pertussis is more common (most of the following
information is taken from Galazka). "Before the introduction of
widespread immunization of young children with pertussis vaccine, the
incidence rates in Europe and the United States were very high. The
reported rates per 100,000 population ranged from 200-300 in England and
Wales and Sweden, to more than 1,000 in Denmark and Norway." (Galazka)
Annual incidence in the US and Canada before the introduction of pertussis
vaccine in the 1940s ranged from 98 to 210 per 100,000 population. After
the introduction and widespread use of DTP vaccine, incidence declined
dramatically in most countries, and this trend continued for about 20
years. For example, in England and Wales, more than 150,000 cases of
pertussis were reported a year in the 1950s; by 1973, when vaccine
acceptance was over 80%, only about 2,400 cases were reported.
However, in the late 1970s and the 1980s, different trends began to
appear in different European countries. In one group of countries,
reported incidence is between 10 and >100 per 100,000. This group
includes Sweden and Italy, which don't routinely give pertussis vaccine
to infants. It also includes Germany, the former USSR, Ireland, Spain,
and the United Kingdom, where infants are routinely vaccinated, but
coverage is less than 80%. In Denmark, incidence is high despite high
coverage, but Denmark uses a different vaccination schedule from the
other countries. Countries with a moderate reported incidence (between 1
and 10 per 100,000) include Austria, Finland, Greece, Israel, Norway, the
Netherlands, Portugal, Romania, and Yugoslavia. Countries with a low
incidence (less than 1 per 100,000) include Hungary, Switzerland, Bulgaria,
Czechoslovakia, Poland, and Turkey.
Q3a.7 How effective is the whole cell pertussis vaccine?
It's one of the less effective childhood vaccinations. The PDR
estimates its effectiveness at 70-80%. It's effectiveness rating
depends on the severity of the cases of pertussis being observed. One
study of 1797 households found the vaccine to be 64% effective against
a mild cough, 81% effective against a paroxysmal cough, and 95%
effective against severe clinical illness. "Requiring laboratory
confirmation improved efficacy to 95 to 98% for culture-positive
children and to 77% to 95% for culture- or serology-confirmed cases,
depending on disease severity. Vaccine efficacy for typical
paroxysmal cough increased from 44% for one diptheria, tetanus, and
pertussis vaccine to 80% for four or more doses." (Onorato, Wassilak,
and Meade) The variation in estimates of efficacy may be because the
more severe cases were more likely to actually be pertussis, or it may
be that the vaccine protects better against severe pertussis than
against a mild form of the disease. Note: these effectiveness ratings
are for the older, whole cell pertussis vaccine. For information on
the effectiveness of the newer, acellular vaccines, which is
generally comparable to that of the older whole cell vaccines, see
below.
Q3a.8 How long does the pertussis vaccine last?
It doesn't. According to _Harrison's Internal Medicine_, "the
protection ... is transient, with minimal resistance being evident a
decade later." However, the critical years for pertussis immunity are
when a child is young; the disease is not dangerous for adults.
With introduction of the new, less reactogenic acellular vaccine,
it is possible that boosters may eventually be given to adults.
(This estimate is for the older, whole cell vaccine, but the
newer acellular vaccine is apparently at least as durable as
the whole cell one was.)
Q3a.9 What is tetanus, and what are the risks of the disease?
Tetanus is very dangerous. Even with antibiotics, mortality can be 40%
or higher (Pantell, Fries, and Vickery, Harrison). Tetanus bacteria and
its spores are everywhere. Because tetanus is so ubiquitous, the only
way to counter it is widespread vaccination.
300,000 to 500,000 cases are reported worldwide, with a mortality of about
45%. In the US, there are about 100 cases a year, with a mortality of
40-60% (Harrison).
Q3a.11 How effective is the tetanus vaccine?
According to Taking Care of Your Child, "Tetanus is one of our best
immunizations.... Of all the vaccines available, tetanus comes closest
to 100 percent effectiveness after the initial series of shots."
Q3a.12 How long does the tetanus vaccine last?
Generally ten years. In the case of a really dirty wound, a booster
is recommended if the person hasn't been vaccinated for tetanus within
the last five years.
Q3a.13 What are some of the risks of the DTP vaccine?
DTP, particularly in its earlier form (with the whole cell pertussis
component) is probably the most controversial of the childhood vaccines,
because of risks associated with its pertussis component. Anecdotal
evidence has linked the vaccine with a variety of problems, including
convulsions, physical collapse, brain damage and SIDS. Supporters of
the vaccine have argued that these problems are common in any case at
the age at which children are vaccinated for pertussis, and therefore
are not necessarily effects of the vaccine.
The association between DTP and SIDS has not been confirmed by further
study (see Q1.5 for a study which found the evidence to be against such an
association). The story on brain damage is somewhat different. Criticism
of the pertussis vaccine received some confirmation in 1976, when a large
British study of all children 2 to 36 months old in Britain found that 1
in 310,000 doses resulted in permanent brain damage.
Critics argue that the rate of complications from the pertussis
vaccine is too high, and the effectiveness too low. Some argue that
the decline in pertussis cases in this century has been an effect more
of improved sanitation than of the pertussis vaccine. The side
effects of this vaccine have inspired groups critical of vaccination
in several countries, including the US, where the group Dissatisfied
Parents Together (DPT) has lobbied Congress for changes to laws about
vaccination and set up its own vaccine information center.
Supporters of the pertussis vaccine differ in their response to the
British study which linked pertussis to brain damage. Some say that
further analysis indicates that a link between the vaccine and brain
damage is not so clear. "Meticulous reexamination of the data from this
study led to the conclusion that the preliminary results were due to a
systematic bias that favored finding an association between the vaccine
and serious neurological sequelae. In fact, there was no valid evidence
from the study that the vaccine was associated with permanent
neurological damage." (Shapiro)
Some smaller studies done since the British study didn't find a connection
between DTP vaccine and neurological damage, and a new study was just
published in the Journal of the American Medical Association which finds
no increased risk of serious neurological illness. I haven't seen the
article yet, so my information comes from the January 11, 1994 San Jose
Mercury (from the New York Times news service), which reports that the
study is in the current (as of 1/11/94) issue of JAMA. According to the
article, "The federally financed study, the largest of its kind in the
United States, involved 218,000 children up to 24 months old in Oregon and
Washington who were studied for a one-year period, beginning Aug. 1,
1987." However, the study is also described as "not intended to give a
definitive answer to the question of whether whooping cough vaccine causes
neurological illness."
Others do not dispute the 1976 British study, but argue that a 1 in
310,000 risk of brain damage is still much smaller than the risk of
actually getting pertussis. Supporters agree that it is important to
maintain high vaccination levels against pertussis, lest we see a
resurgence in the disease. In Great Britain, Japan, and Sweden, there
were sharp increases in the number of cases of pertussis when vaccination
levels fell. Routine use was discontinued in Sweden as a result of
reports of side effects, while acceptance in Great Britain declined to 30%
(Harrison), and vaccination declined in Japan as well. "Within two years,
one hundred thousand cases (with twenty-eight deaths) appeared in Great
Britain and thirteen thousand cases (with forty-one deaths) in Japan.
Even in the US, the disease has by no means been wiped out; there are
still about fifteen hundred to two thousand cases (with four to ten
deaths) each year. That is why virtually all health care authorities
recommend that we keep using this vaccine." (UC Berkeley)
ACIP considered the available data on brain damage in 1991, and
concluded that "Subsequent studies have failed to provide evidence
to support a causal relation between DTP vaccination and either
serious acute neurologic illness or permanent neurologic injury."
It further noted that "The risk estimate from the NCES study of
1:330,000 for brain damage should no longer be considered valid
on the basis of continuing analysis of the NCES and other
studies." (Staff, Diptheria, tetanus, and pertussis: recommendations
for vaccine use and other preventive measures, in Recommendations
of the Advisory Committee on Immunization Practices (ACIP). Aug 8,
1991, CDC: Atlanta. p. 1-21.)
Known and non-controversial (i.e. everyone agrees that they occur) side
effects of DTP vaccine include redness and tenderness at the injection
site, fever, drowsiness, fretfulness, vomiting, and convulsions. (A
vaccine information pamphlet from Kaiser gave the frequency as being 1 in
100 to 1 in 1000 for crying without stopping for three hours or longer, a
temperature of 105 F or greater, or an unusual, high-pitched cry, and 1 in
1,750 for convulsions, generally from high fever, or shock collapse. I
didn't see any frequencies in the PDR, other than describing these side
effects as rare.) It is a good idea to give acetaminophen to children
being vaccinated for pertussis, to reduce the chance of fever and febrile
convulsions.
This claim is examined at length by Lon Morgan, DC,DABCO in his
Web site "A summary of JAPAN, SIDS, and PERTUSSIS IMMUNIZATION"
at http://fp1.cyberhighway.net/~lmorgan/fearmongers/japan_sids.htm.
It turns out that what went away, in 1975, when Japan increased
the age at which it administered the first dose of the
vaccine from three months to two years, was *claims of vaccine
injuries* for SIDS. Japan had a compensation system for
vaccine injuries, in which claims were to be paid unless other
causes were clearly provable. Under this system, 11 claims
were paid for what was termed Sudden Death, between 1970-1975
(this out of 25-30 million doses of pertussis vaccine). After
the vaccination age was raised, no further claims were paid
for Sudden Death related to vaccination. Since SIDS occurs
before 12 months of age, any cases of SIDS can not be attributed
to a vaccine which is given starting at 24 months.
Japan has, however, kept statistics for SIDS, and these
statistics showed the numbers of SIDS cases *increasing*,
rather than decreasing, at the time that the age of the
first pertussis vaccination was raised. Though the delay
in age for the first pertussis vaccination did not reduce
the incidence of SIDS, it did result in a huge increase in
pertussis cases, peaking at 13,105 cases and 41 deaths by
1979. For more details, and references, see Lon Morgan's
site.
As a side note, recent vaccination rates for Japan, as
listed in http://www.who.int/gpv-surv/country/japan.html,
were, in 1996, 98% for polio, 100% for diptheria, pertussis,
and tetanus, and 94% for measles; the coverage for BCG in
1993 was 91%.
Q3a.15 When is the DTP vaccine contraindicated?
Hypersensitivity to a vaccine component, including thimerosal, a
mercury derivative. Defer vaccination in case of fever or acute
infection (but not nececcarily for a mild cold without a fever).
A history of convulsions is generally a contraindication to
pertussis vaccination, but "The ACIP and AAP recognize certain
circumstances in which children with stable central nervous system
disorders, including well-controlled seizures or satisfactorily
explained single seizures, may receive pertussis vaccine. The ACIP
and AAP do not consider a family history of seizures to be a
contraindication to pertussis vaccine." (PDR)
The following reactions to a previous dose are contraindications:
An immediate anapylactic reaction. Encephalopathy occuring within
7 days following DTP vaccination. Precautions include a fever of
>= 40.5 C (105 F) within 48 hours, collapse of shocklike state
within 48 hours, persistent inconsolable crying for more than 3 hours
within 48 hours, convulsions with or without fever within 3 days.
(These latter are precautions rather than contraindications, because
there might be circumstances, such as a pertussis epidemic, where you
would still want to give the vaccine.)
Pertussis vaccine should not be given to anyone over seven years old
(this may change, in time, with the new acellular vaccine, but further
study is needed first).
Vaccine components capable of causing adverse reactions: for diptheria,
thimerosal and toxoid; for tetanus, thimerosal and toxoid; for pertussis,
bacterial components (Travel Medicine Advisor).
(Note: There is currently, as of 1999, a move toward replacing thimerosal
in vaccines, so the reference to thimerosal here may shortly be out of
date.)
Q3a.16 What are the advantages and disadvantages of the new acellular
pertussis vaccine?
The big advantage is that the acellular vaccine has fewer side effects.
The FDA initially held off on approving it for the earlier shots (while
approving it for the fourth and fifth shots), mainly due to remaining
uncertainty as to whether it is as effective as the whole cell vaccine.
Reports from Japan indicated that it is, but a Swedish clinical trial
indicated efficacy of 59% for one, and 64% for the other acellular vaccine.
However, even this trial did show >90% efficacy against severe pertussis.
(Shapiro) More recent results in Sweden and Italy indicate it is both
safe and effective. On July 31, 1996, the FDA licensed one acellular
pertussis vaccine for the inital three shots, and more followed. The
American Association of Pediatrics has issued guidelines for the use of
the new vaccine, which can be found at their web page, http://www.aap.org.
As of 7/14/95, results were available from two large European studies,
involving 9,829 infants in Sweden and 15,601 infants in Italy. The
National Institute of Allergy and Infectious Disease (in the US) reported
that "three similar experimental vaccines effectively immunized 84% to 85%
of the children in the trials, while resulting in fewer side effects than
current, widely used versions." (Wall Street Journal, 7/14/95, p. A7A) A
surprising result of the studies was that whole cell pertussis vaccine
efficacy rates were lower than usual: "conventional vaccines provided
protection for just 36% of children in Italy and 48% in Sweden. In the US
the conventional vaccine proves effective in 70% to 95% of the children
who are vaccinated." Officials suggested that infants in these studies
might have had a higher intensity of exposure to the bacteria due to the
lack of widespread vaccination in those countries, and that might explain
the lower efficacy. A fourth acellular vaccine provided protection in 58%
of the cases. The high efficacy and low side effects shown for the
acellular pertussis vaccine in these studies will likely lead to requests
that the FDA also approve the acellular vaccine for the earlier pertusis
shots. More information on recent study results can be found in NEJM, Vol.
333, Number 16, Oct. 19, 1995 (B. Trollfors and others).
Despite the acellular vaccine's comparable efficacy and few adverse reactions,
the whole cell pertussis vaccine retains one advantage which ensures some
continued use. It is cheaper, and more organizations know how to make it
In developing countries, where pertussis is a major killer, and money for
vaccines in short supply, it is not clear that the advantages of the
acellular vaccine justify the additional cost.
Q3a.17 What are some of the risks of the DT (diptheria and tetanus)
vaccine?
Most of the risk in the DTP vaccine comes from its pertussis component;
the diptheria and tetanus vaccines are quite safe. Reactions to the
diptheria vaccine are quite rare. Most reactions are local, limited to
swelling at the injection site. The same is true of the tetanus shot.
"Severe local reactions can occur if too many shots are received; this
phenomenon was frequently seen in military recruits who received unneeded
immunizations." (Pantell, Fries, and Vickery)
Q3a.18 When is the DT vaccine contraindicated?
Should be avoided during the first trimester of pregnancy. People
who have had a reaction (which is very rare) should avoid it.
Vaccine components capable of causing adverse reactions: for diptheria,
thimerosal and toxoid; for tetanus, thimerosal and toxoid (Travel Medicine
Advisor).
(Note: There is currently, as of 1999, a move toward replacing thimerosal
in vaccines, so the reference to thimerosal here may shortly be out of
date.)
Q3a.19 Under what circumstances is tetanus toxoid given to pregnant
women?
Tetanus toxoid is given to pregnant women in countries where there is
a high risk of neonatal tetanus (due to factors which enhance the risk
of cord contamination in these countries).
===============================================================================
Q3b.1 What is polio, and what are the risks of the disease?
Polio is a contagious viral disease which crippled tens of thousands
in the 1950s, and killed more than a thousand a year. Because it is a
mild gastrointestinal illness in young children and a serious
paralytic illness in older people, it had an unusual epidemiology,
with more cases of paralytic polio turning up in wealthy areas and as
sanitation improved. 80-90% of cases of polio are the minor illness;
the rest are paralytic poliomyelitis. In paralytic poliomyelitis, <
25% suffer permanent severe disability, about 25% have mild
disabilities, and > 50% recover with no residual paralysis. Mortality
is 1 to 4%. "Recently, a post poliomyelitis syndrome has been
described, characterized by muscle fatigue and decreased endurance...
The syndrome occurs many years after an attack of paralytic
poliomyelitis..." (Merck).
Q3b.2 How effective is the polio vaccine?
The Merck Manual and the Physician's Desk Reference give its
effectiveness as 95%. An article in a WHO publication (Hull and Ward)
estimates effectiveness at 80%. (As with other WHO estimates, the
lower effectiveness rating reflects an estimate of effectiveness in
the field in a variety of countries, including countries in the Third
World. Polio vaccine effectiveness can deteriorate if it is exposed
to too much heat, which can happen in vaccination programs in some
countries.)
Q3b.3 How long does the polio vaccine last?
It provides lifelong immunity.
Q3b.4 What is the difference between oral polio vaccine (OPV) and
inactivated polio vaccine (IPV)?
Oral polio vaccine provides better immunity, and was until recently
usually the recommended form, "because induces intestinal immunity,
is simple to administer, is well accepted by patients, results in
immunization of some contacts of vaccinated persons, and has a record
of having essentially eliminated disease associated with wild poliovirus
in this country." (PDR) However, it carries a small risk of paralysis
(see the answer to the next question for details).
Recently, with increased progress in worldwide eradication of polio,
both ACIP and AAP have changed their recommendation to IPV for all
shots. OPV remains the vaccine of choice for countries where polio
is still endemic, and for people who will be shortly travelling to
such countries.
Q3b.5 I've heard that it is possible to contract polio from handling
the diapers of recently immunized infants. How long after receiving
the vaccine does the child's excrement continue to contain the virus?
Q3b.6 What are some other risks of the polio vaccine?
A small risk of anaphylactic shock.
Q3b.7 When is the polio vaccine contraindicated?
Because of the small risk of paralytic polio in recipients and contact
of recipients of OPV, it should not be given to anyone who is
immune-compromised or who has immune-compromised family members. (The
PDR has a really long list of immune deficiencies involved, which you
can check if you think anyone in your family falls in this category.)
In these cases, IPV should be given instead. IPV is also recommended
for adults who are at risk for polio (such as unvaccinated adults
travelling to an area where polio is endemic). Both vaccines are
contraindicated for people with an anaphylactic allergy to neomycin or
streptomycin.
Vaccine components capable of causing adverse reactions: for both OPV
and IPV, streptomycin, neomycin, and phenol red; for IPV, animal
protein, formaldehyde, and polymyxin B (Travel Medicine Advisor).
Q3b.8 Isn't it true that wild polio has been eliminated in the US?
Q3b.9 Why are we still vaccinating for polio, then?
The AAP and ACIP continue to recommend vaccination for polio for
several reasons. First, the risk of the disease is much higher than
the risk of the vaccine. Second, though there is no wild polio in the
US *now*, with high levels of vaccination, there is still polio
elsewhere in the world. 148,000 cases were reported to WHO in 1990.
China reported 5,065 cases. The USSR reported 337 cases. India
reported 7,340. (Hull and Ward) There have been several outbreaks of
polio in countries 2 or more years after the last reported case of polio.
Importation from polio endemic countries has led to outbreaks in Oman
(1988-89 and 1993), Jordan (1991-92), Malaysia (1992), and the Netherlands
(1992-93) (MMWR, reported in HICNet Medical News on 15 August 1994).
Wild poliovirus type 3 was isolated during January-February 1993 among
members of a religious community objecting to vaccination in Canada
(although no actual cases of parlytic polio occurred in Canada at this
time). There is a concern that if levels of vaccination were reduced in
the US, polio could be reintroduced, and we could see polio epidemics here
again.
Encouraged by the worldwide elimination of smallpox, WHO, in 1988, set
a goal of eradicating polio from the world by 2000. Since then, the
number of cases in the world has declined dramatically (29,916 in 1989
and 16,435 in 1990), and the number of countries reporting 0 cases has
increased (74 countries in 1985 and 116 countries in 1990). As of 1993,
the number of cases worldwide has falled to 9714, and nearly 70 percent
of all countries reported no cases. (Progress toward global eradication of
poliomyelitis, 1988-1993. MMWR 1994 Jul 15; 43:499-503. Summarized in
Journal Watch Summaries for July 22, 1994.) As of 1999, WHO reports still
further progress, "In 1988, virus circulated widely on all continents except
Australia. By 1998, the Americas were polio-free (certification of
eradication in 1994), transmission has been interrupted in the Western
Pacific Region of WHO, including China, and in the European Region, except
for a small focus in south-east Turkey. As shown below, only three major
foci of transmission remain: South Asia (Afghanistan, Pakistan, India),
West Africa (mainly Nigeria) and Central Africa (mainly Democratic
Republic of Congo)." So another factor in the decision to continue
vaccinating for polio is the hope that it can be eliminated for good.
After much debate, the US has switched to IPV instead of OPV
(IPV being less effective, but lower in side effects). The decision at
first was to continue with OPV because it has been so successful, the
rate of side effects is still considered very low, and because of various
advantages in producing immunity (see above). According to the 1993 PDR,
"The choice of OPV as the preferred poliovirus vaccine for primary
administration to children in the United States has been made by the ACIP,
the Committee on Infectious Diseases of the American Academy of Pediatrics,
and a special expert committee of the Institute of Medicine, National
Academy of Sciences." In 1995, though, that decision was changed, and
the injected vaccine became recommended for the first two polio shots.
As progress toward worldwide polio eradication continued, and as the
change in the vaccination schedule (from an oral to an injected form)
did not result in any decline in vaccination coverage, ACIP and AAP
are now recommending IPV for all shots.
===============================================================================
Q3c.1 What is measles, and what are the risks of the disease?
Measles is one of the most contagious infectious diseases. "A child can
catch measles by breathing the air in a doctor's waiting room two hours
after an infected child has left." (Fettner) 90% of susceptible
household contacts get the disease (Harrison). Measles spreads very
rapidly in unexposed populations. In 1951, it was introduced to
Greenland by a recently arriaved visitor who went to a dance as he was
coming down with it, and in three months it spread to more than 4000
cases and 72 deaths. The attack rate was 999 cases per 1000 people. In
1875, measles was introduced to Fiji and killed 30 percent of the
population (Smith).
In areas where it was endemic, before the measles vaccine, measles
epidemics used to occur at regular intervals of two to three years,
usually in the spring, with small local outbreaks in intervening years.
Mortality is low in healthy, well-nourished children unless complications
ensue (Merck), but nevertheless there were 400 deaths a year before an
improved measles vaccine was introduced in 1966 (Pantell, Fries, and
Vickery). Complications include brain infection, pneumonia, convulsions,
blindness, various bacterial infections, encephalitis, and SSPE (a fatal
complication which can occur years after a person has had measles).
Pregnant women who get measles have a 20% chance of miscarriage.
Worldwide, measles is one of the leading causes of childhood mortality.
"Measles has been called the greatest killer of children in history."
(Clements, Strassburg, Cutts, and Torel) In 1990, "45 million cases and
around 1 million deaths were estimated to occur in developing countries.
Thus measles is still responsible for more deaths than any other EPI
target diseases. The true number dying as a result of measles may be
twice the estimated 1 million if the recently documented delayed effect
of the disease is taken into account." (Ibid.) Mortality is higher in
developing countries due to a difference in the age at which most people
catch it (measles is a more dangerous disease in the very young), poorer
nutrition, less availability of treatment for bacterial chest infections,
and other environmental factors. However, "Even in countries with
adequate health care and healthy child populations, the complication rate
can reach 10%." (Ibid.)
More information on the incidence of measles complications is found in
the answer to Q3c.2.
Q3c.2 How common was measles before routine vaccination, and how
common is it now?
Q3c.3 How effective is the measles vaccine?
The Merck Manual and the Physician's Desk Reference estimate its
effectiveness at 95%. This estimate is based on studies of the
immunity induced by a series of vaccinations beginning at 15 months.
Another article, estimating the immunity induced in field conditions
(including some Third World countries, which may have less reliable
vaccine storage) by a series of injections beginning at 9 months (the
injections are started earlier in areas where measles is widespread),
estimated effectiveness as 85% (Clements, Strassburg, Cutts, and
Torel).
A recent article in Pediatric News (Imperio. Vaccine-Exempt At Higher Risk For Measles.
Pediatric News 33(9):9, 1999.) reported that "Individuals aged 5-19 years who were not
vaccinated due to religious or philosophical exemptions were, on average, 35 times more
likely than vaccinated individuals to contract measles, according to a population-based,
retrospective cohort study."
Q3c.4 How long does the measles vaccine last?
The Merck Manual describes it as "durable." The PDR says that all of the
antibody levels induced by MMR have been shown to last up to 11 years
without substantial decline, and "continued surveillance will be
necessary to determine further duration of antibody persistance."
Q3c.5 What are some of the risks of the measles vaccine?
There is a small chance of complications similar to the complications of
measles (pneumonia, encephalitis, SSPE). Information on the frequency of
these complications is included in the answer to Q3c.2. There is some
risk of anaphylaxis. This risk is low; from the time that VAERS was
instituted in 1990 till the publication of Update: Vaccine Side Effects,
Adverse Reactions, Contraindications, and Precautions by ACIP in 1996,
>70 million doses of MMR vaccine had been distributed in the US, and
only 33 cases of anaphylactic reactions had been reported to VAERS.
It has been traditionally believed that this risk is mainly for people
allergic to eggs or neomycin. However, recent studies indicate that
anaphylactic reactions are not associated with egg allergies, but with
some other component of the vaccine. There have been some case reports,
in the US and Japan, of anaphylactic reactions to the MMR vaccine in
people with an anaphylactic sensitivity to gelatin.
In rare instances, MMR vaccine can cause clinically
apparent thrombocytopenia within 2 months after vaccination.
Passive surveillance systems report an incidence of 1 case per
100,000 doses in Canada and France, and 1 per million in the US.
Prospective studies have reported a range from 1 in 30,000 in
Finland and Great Britain to 1 in 40,000 in the US, with a
clustering of cases about 2-3 weeks after vaccination.
An article in the Feb 28, 1998 Lancet (based on 12 cases) about
a possible association between inflammatory bowel disease, autism,
and MMR vaccine (Wakefield et al) raised concerns that the vaccine
might increase the risk of autism. Wakefield and his colleagues
did not claim to have actually shown that the vaccine caused
autism, but rather called for further investigation of the
question. An accompanying editorial in the same issue of
Lancet expressed concerns about the validity of the study.
The article, and the public concern it raised, led to several
further investigations of whether such an association existed.
A research letter in the May 2, 1998 issue of Lancet
reported on a 14-year prospective study, in Finland, of children
who had experienced gastrointestinal symptoms after receiving
the MMR vaccine. 31 children (out of 3 million vaccine doses)
reported gastrointestinal symptoms; all recovered, and none
developed autism. A Working Party on MMR Vaccine of the
United Kingdom’s Committee on Safety of Medicines (1999)
examined hundreds of reports, collected by lawyers, of autism
or Crohn's disease (a gastrointestinal disease) and similar
problems, after the MMR vaccine, and concluded that there
was no causal relationship. A Swedish study (Gillberg and
Heijbel 1998) found no difference in the prevalence of autism
in children born before the introduction of MMR vaccine in
Sweden, and children born after. Wakefield and colleagues
did laboratory assays in patients with inflammatory bowel
disease (the mechanism which they had proposed for autism
following the MMR vaccine), and found them negative for
measles virus (Chadwick 1998, Duclos 1998, cited by
the CDC at
http://www.cdc.gov/nip/vacsafe/vaccinesafety/sideeffects/autism.htm).
Finally, a study in the June 12, 1999 issue of Lancet
examined children born with autism since 1979
in eight North Thames health districts, to look for
changes in incidence or age at diagnosis since the
introduction of MMR vaccination in the UK in 1988.
The study found a steady increase in cases of autism,
with no sudden change in the trend after the introduction
of the MMR vaccine. Parents most frequently reported
first noticing symptoms of autism at around the age of
18 months, after the MMR vaccine would have been received,
but there was no difference in age at diagnosis between
those vaccinated before and after 18 months and those
never vaccinated. Developmental regression (which occurred
in about a third of the cases of autism) was not clustered
in the months after vaccination.
Q3c.6 What is mumps, and what are the risks of the disease?
Mumps is a viral disease which is less contagious than measles or chicken
pox. It causes swollen salivary glands. The most common complication is
swelling of the testes (in about 20 percent of males post puberty) and,
less commonly, ovaries. Rarely, it can lead to sterility. Other
complications are meningitis (less common than in measles) and acute
pancreatitits. (A much longer list of complications can be found in the
Merck Manual.)
Q3c.7 How common was mumps before routine vaccination, and how
common is it now?
105,00 cases were reported in 1970; by 1990 the rate of reported cases
was down to 5,300.
Q3c.8 How effective is the mumps vaccine?
The Merck Manual estimates its effectiveness at 95%. The Physician's
Desk Reference gives its effectiveness as 96%. Switzerland has gotten
lower efficacy rates, for mumps, out of its strain of the MMR vaccine,
and Swiss scientists have been comparing the efficacy of different
strains to improve this situation (Swiss Medical Weekly,
http://www.smw.ch/archive/1997/127-26-360-96.html and
http://www.smw.ch/archive/1998/128-17-351-98.html).
Q3c.9 How long does the mumps vaccine last?
The Merck Manual describes it as "durable." "Mumps immunization provides
protection through the blood serum antibodies for at least 12 years, and
possibly much longer." (Pantell, Fries, and Vickery) (See also Q3c.4 for
the PDR's description of the duration of all the MMR-induced antibodies.)
Q3c.10 What are some of the risks of the mumps vaccine?
"Rarely, side effects of mumps vaccination have been reported, including
encephalitis, seizures, nerve deafness, parotits, purpura, rash, and
prurittis." (Merck. Encephalitis and convulsions were also on Merck's
list of complications for mumps itself.) According to ACIP's 1996
report on vaccine adverse reactions, "Aseptic meningitis has been
epidemiologically associated with receipt of the vaccine containing
the Urabe strain of mumps virus, but not with the vaccine containing
the Jeryl Lynn strain, the latter of which is used in vaccine
distributed in the United States." [MMWR 45(No. RR-12), 1996]
Q3c.11 What is rubella, and what are the risks of the disease?
Rubella is a mild illness, consisting of a mild fever and rash. Rare
complications include ear infections and encephalitis, but the real
danger is to pregnant women. During the last rubella epidemic, in 1964,
20,000 children were born with birth defects caused by rubella. Birth
defects include deafness, cataracts, microcephaly, and mental
retardation. Children born with congenital rubella are als susceptible
to rubella panencephalitis in their early teens.
Q3c.12 How common was rubella before routine vaccination, and how
common is it now?
Before the development of the rubella vaccine, epidemics used to occur at
irregular intervals in the spring, with major epidemics at 6 to 9 year
intervals. (This means that one was just about due when the vaccine came
out in 1969.) There have been no major epidemics since 1969, but the
number of cases of rubella and congenital rubella syndrome increased
starting in 1989 (Merck, also California Morbidity for November 19, 1993).
(It was still a small fraction of the pre-vaccine number, though, see table
of disease frequencies in section 1.) "Serological surveys conducted in
the late 1970s and the 1980s indicated that 10 to 25 percent of United
States women of child-bearing age were shown to be susceptible to
rubella." (California Morbidity, November 19, 1993) It now appears to be
declining again: "Following a resurgence of rubella and congenital rubella
syndrome (CRS) during 1989-1991, the reported number of rubella cases during
1992 and 1993 was the lowest ever recorded." (MMWR, cited in June 9, 1994
HICNet Medical News Digest.)
Q3c.13 How effective is the rubella vaccine?
The Merck Manual estimates its effectiveness at 95%. The Physician's
Desk Reference gives its effectiveness as 99%.
Q3c.14 How long does the rubella vaccine last?
The Merck Manual describes it as "sustained." (See also Q3c.4 for the PDR's
description of the duration of all the MMR-induced antibodies.)
There is still some uncertainty about the most desirable rubella
vaccination policy. In 1969, when the vaccine came out, it was decided
to avert the expected epidemic by vaccinating all children over one year,
so that they would not spread rubella to their possible pregnant mothers
- the first time one group of people was vaccinated to avoid having them
spread a disease to a different group of people. Supporters of this
policy point out that the expected epidemic didn't occur. The possible
disadvantage is that we aren't sure how long the immunity lasts. Now
that generation of children is old enough to have children, and some of
them may no longer be immune. In the past, 80% of the population was
immune due to having had rubella in childhood.
Some countries follow a policy of vaccinating girls at puberty if they
don't have rubella antibodies (Pantell, Fries, and Vickery). The
disadvantage is that vaccine side effects are more common at this age.
The most common is joint pain, which occurs in 10% of women who are
vaccinated in adolescence or later. In some cases, it has lasted as long
as 24 months. (Pantell, Fries, and Vickery) The PDR describes this same
side effect in somewhat milder terms, saying that it generally does not
last very long and "Even in older women (35-45 years), these reactions are
generally well tolerated and rarely interfere with normal activities." It
does agree with Pantell, Fries, and Vickery that the incidence of this side
effect increases with age: 0-3% of children and 12-20% of women have joint
pain, and the pain is more marked and of longer duration in the adult
women. A few women (between 1 in 500 and 1 in 10,000) experience
peripheral neuropathy (tingling hands). Another risk of vaccinating later
is the risk that a woman may be pregnant. So far, no connection with
birth defects has been demonstrated, but women are advised to avoid
pregnancy for three months after getting the vaccination.
Current US policy is to vaccinate all children at 15 months, and give a
booster during school years. Adult women are advised to get an antibody
test before becoming pregnant, and, if it comes up negative, get
vaccinated and wait three months before getting pregnant.
There has not been a rubella epidemic since 1964, either in countries
which vaccinate all children at 15 months, or in countries which
vaccinate girls only at puberty.
Q3c.16 What are some of the risks of the rubella vaccine?
The PDR has a long list of possible adverse reactions (besides arthritis
and arthralgia, usually short-lived, see above). Most of them are either
mild or rare.
Q3c.17 When is the MMR vaccine contraindicated?
People with an anaphylactic or anaphylactoid allergy to eggs or neomycin
should not get the vaccine. Other allergies or chicken or feather allergies
are not a contraindication. Vaccination should be deferred in case of
fever. The PDR give active untreated tuberculosis as a contraindication,
but the AHFS says that there is no evidence of a need to worry about TB.
Both give immune deficiency as a contraindication (see PDR for a long
list of immune deficiencies involved). Immune globulin preparation or
blood/blood product received in the preceding 3 months. The same
contraindications apply individually to measles and mumps vaccines, but
the rubella vaccine can be given by itself to people with an anaphylactic
egg allergy. The other contraindications still apply to the rubella
vaccine alone. (California Morbidity, October 31, 1987)
Vaccine components capable of causing adverse reactions: for mumps
and measles, chick fibroblast components; for mump, measles, and
rubella, neomycin (Travel Medicine Advisor).
===============================================================================
Q3d.1 What is hemophilus influenze B, and what are the risks of the
disease?
HiB is a bacteria which is one of the leading causes of meningitis in
young children. About 60% of cases are meningitis. The remaining 40%
are cellulitis, epiglottis, pericarditis, pneumonia, sepsis, and septic
arthritis. Mortality rate can be about 5%, and there are neurologic
sequelae in up to 38% of survivors.
Q3d.2 How common was HiB before routine vaccination, and how
common is it now?
Before routine vaccination, about 12,000 cases a year in the US, with a
cumulative risk of 1 in 200 that a child would get the disease by age 5.
A vaccine was introduced in 1985. Since the introduction of the Hib conjugate
vaccine in 1988, the race-adjusted incidence of Hib among children less than 5,
has declined from 41 cases per 100,000 in 1987 to two cases per 100,000 in
1993. (The incidence for people five or older remained stable. Hib is most
serious in children under 5.) (A decline of 95%, despite the fact that the
National Health Interview Survey showed only 67% of children 12-23 months
had received at least one dose, and 36% three or more doses. This decline
is attributed to the elimination of carriage, which reduces Hib exposure
even in unvaccinated children.) The CDC set a goal of eliminating Hib in
the US by 1996. (HICN708 Medical News, "[MMWR] Progress Elimination
Haemophilus influenzae type b") As of September 1999, this goal wasn't
met, but there has been a significant decline; MMWR's "TABLE III.
Provisional cases of selected notifiable diseases preventable by
vaccination, United States week ending September 11, 1999" records a
cumulative total for 1998 of 788 cases, and for 1999 of 820 cases, in
the US.
Q3d.3 How effective is the HiB vaccine?
Estimates from different labs vary a lot. AHFS Drug Information,
after noting this variability, and the uncertainty as to what antibody
level is adequate for protection, says that in one study, 75% of
children 18-23 months and 85% of children 24-29 months had serum
anticapsular antibody levels of one microgram per milliliter or
greater. The PDR lists numerous studies, with results ranging from
100% efficacy to one study in which vaccinated children had more cases
of HiB than the unvaccinated group. With the exception of the latter
study, all of the studies showed significant positive results, often
with efficacy estimates over 90%.
According to a NY Times article of 12/18/90, HiB vaccine produces
lower antibody response among Native Americans, but the new conjugated
vaccine seems to produce higher antibody response in Native American
children and may protect all children at a younger age.
Q3d.4 How long does the HiB vaccine last?
The duration of immunity is unknown. However, the disease is only
dangerous to very small children.
Q3d.5 What are some of the risks of the HiB vaccine?
In a study of 401 infants, fever occurred in 2%, and redness, warmth, or
swelling in 3.3%. All adverse reactions were infrequent and transient.
(PDR) The Institute of Medicine reported in 1994 that evidence favored
rejection of a causal relationship between early onset HiB disease
and conjugate vaccines, but favored acceptance of a causal relationship
between early onset disease in children 18 months old or more whose
first vaccination was with unconjugated PRP vaccine. [MMWR 45(No. RR-12),
1996]
Q3d.6 When is the HiB vaccine contraindicated?
Hypersensitivity to any component of the vaccine, including diptheria
toxoid and thimerosal in the multi-dose presentation.
Vaccine components capable of causing adverse reactions: phenol,
bacterial polysaccharides, thimerosal (Travel Medicine Advisor).
(Note: There is currently, as of 1999, a move toward replacing thimerosal
in vaccines, so the reference to thimerosal here may shortly be out of
date.)
Q3d.7 What about rifampin prophylaxis?
An alternative to HiB vaccination is rifampin prophylaxis, but it
could be unwieldy to administer. AHFS Drug Information says that it
is "effective for eradicating nasopharyngeal carriage of HiB, but the
efficacy of the drug for prevention of secondary disease has not been
firmly established."
===============================================================================
Q3e.1 What is hepatitis B, and what are the risks of the disease?
There are several forms of hepatitis, infections of the liver which
cause jaundice, nausea, and weakness. Hepatitis B is spread mainly by
contact with infected blood and by intimate contact with bodily fluids,
such as in sexual intercourse and childbirth. However, the hepatitis
B virus is far more resilient than, for example, the AIDS virus, and
the disease is not strictly a venereal disease, and can be caught even
by people who are not sexually active. Hepatitis B becomes chronic
in 5-10% of those infected. Complications include hepatic necrosis,
cirrhosis of the liver, chronic active hepatitis, and hepatocellular
carcinoma. Hepatitis B is endemic throughout the world, and a serious
problem in groups at increased risk. Information about hepatitis B
is available by calling 1-800-HEP-B-873. Another source of information
about hepatitis B and many other forms of liver disease is:
http://cpmcnet.columbia.edu/dept/gi/disliv.html
A US government source of information on hepatitis is:
Q3e.2 How common is hepatitis B?
"The estimated lifetime risk of HBV infection in the United States
varies from almost 100% for the highest risk groups to approximately
5% for the population as a whole." (PDR) The CDC estimates about
0.75 - 1 million chronic carriers in the US, and more than 170 million
are estimated worldwide.
Q3e.3 What is hepatitis B gamma globulin, and when is it given?
It is given to people who have already been exposed to hepatitis B, to
boost their immunity. In particular, it is given to children born to
mothers with hepatitis B. It should be given as soon as possible
after birth for the best results.
Q3e.4 How long does the immunity provided by hepatitis B gamma
globulin last?
Two months, maybe longer.
Q3e.5 What are the risks and contraindications of hepatitis B gamma
globulin?
No known contraindications. A couple of diseases (see PDR for more
information) are listed under precautions (a weaker form of warning than
contraindication - in the case of precautions gamma globulin may be given,
but the extra risks of giving the gamma globulin have to be weighed against
the benefits). These diseases, though, aren't ones a newborn is likely to
have, so they would probably not apply in the case of giving it to
the newborn of a mother infected with hepatitis B.
Q3e.6 How effective is the hepatitis B vaccine?
It varies depending on the age, sex, and general health of the
recipient. About 96-100% in infants and children 19 and under, 94-99%
in adults 20-39, 88-91% in adults 40 or older. May be lower in men
than women. Lower (only 64% in one study) in hemodialysis patients.
(AHFS Drug Information 1992) The PDR estimated 95-96% for infants,
and agrees with AHFS about the conditions which reduce effectiveness.
Q3e.7 How long does the hepatitis B vaccine last?
There is evidence that immunity lasts up to ten years, but beyond that,
the duration is uncertain, and the need for booster doses not defined.
(My source for the duration is Journal Watch, 9/1/93.)
Q3e.8 What are some of the risks of the hepatitis B vaccine?
Hepatitis B has traditionally been considered one of the
safest and least reactogenic vaccines:
"During clinical studies involving over 10,000 individuals distributed
over all age groups, no serious adverse reactions attributable to vaccine
administration were reported." (PDR, 1993) The most common adverse reactions
were injection site soreness (22%) and fatigue (14%). A longer list of
adverse reactions can be found in the PDR. "Update: Vaccine Side Effects,
Adverse Reactions, Contraindications, and Precautions," published by
ACIP in 1996, reported that VAERS data showed a low rate of anaphylaxis
(approximately one event per 600,000 doses given).
More recently, controversy has been aroused by news reports,
particularly in France, of new or reactivated cases of multiple
sclerosis, and other demyelinating disorders, within two to
three months following administration of hepatitis B vaccine.
Critics argue that the risk is too high for a vaccine routinely
given to children not directly at much risk for hepatitis B.
Supporters of vaccination argue that, given the demonstrated
risk of liver cancer and cirrhosis of the liver from hepatitis B,
effective vaccination programs should not be abandoned for a
hypothetical risk that the vaccine might in rare cases lead to
multiple sclerosis and other demyelinating diseases.
As is the case in other controversies about vaccination risks,
part of the difficulty is assessing just what effect the
hepatitis B vaccine may have on demyelinating diseases. Multiple
sclerosis is, in some countries, the most common neurological
disease of young adulthood. Though most commonly reported
between 20 and 40, it can be reported at younger and older ages,
and, given near universal vaccination of pre-adolescents, some
cases of MS are to be expected, simply by chance, in proximity
to vaccination. Since the incidence of cases of multiple
sclerosis attributed to the vaccine, in France and elsewhere,
is less than the number already expected for the age range in
question, statistical analysis is required,
to determine whether the risk of MS and other demyelinating
diseases is in fact higher in populations vaccinated for hepatitis
B, and, if so, what the risk might be.
Several studies have been carried out, to date, to assess this
risk, and more are ongoing.
ACIP reported, in 1996, that evidence was inadequate to
establish or reject a causal relationship between hepatitis
B vaccine and demyelinating diseases of the central nervous
system.
The French National Drug Surveillance Committee studied
people who received more than 60 million doses of hepatitis
B vaccine between 1989 and 1997, and found that the prevalence
of neurological disease, including MS, was actually lower in
this group than in the general population.
Three French studies, prompted by reports of MS, showed
a slightly increased relative risk in the vaccinated population,
but not one which was statistically significant. In response
to this, the French government required a risk-benefit analysis.
The risk-benefit analysis did not attempt to determine whether
the hepatitis B vaccine in fact causes MS or other demyelinating
diseases, but rather to use the largest possible risks which
could be derived from the studies which had been done, and
weigh these against the expected benefits of hepatitis B
vaccine (with both being assessed in a statistical, quantititive
fashion). This study concluded that, though it isn't
possible to determine yet whether there is an association
between the hepatitis B vaccine and MS, the benefits of the
vaccine for a given vaccinated pre-adolescent cohort would
clearly outweigh the risks.
In Canada, the Alberta Ministry of Health reported that
a preliminary examination of hospital admission data
between 1975 and 1995 suggests that the introduction of the
hepatitis B vaccine in the mid-1980s has not been marked
by an increase in the incidence of multiple sclerosis.
The World Health Organization Viral Hepatitis Prevention Board
(VHPB) assembled experts, on September 28-30, 1998, to review
the epidemiology and current understanding of MS. This group
examined data on the epidemiology of hepatitis B, the
epidemiology of multiple sclerosis, from national reporting
systems in the US, Italy, and Canada, from one active
pediatric surveillance system in Canada, from industry
post-marketing surveillance and clinical data, from
published studies of hepatitis B safety, and from preliminary
reports of a small number of unpublished epidemiological studies
in the US, France, and the UK. They tried to decide between
three hypotheses for explaining the relationship between
the hepatitis B vaccine and MS: 1) coincidence, 2) "triggering,"
in which an illness which would have occurred anyway was
unmasked by the vaccine, or 3) a true causal relationship.
Evidence for the hypothesis of coincidence included the
lack of any statistically significant association with MS to
date, and the fact that age and sex distributions of
reported adverse events resemble age and sex distributions
seen before the vaccine. Evidence in support of an increased
risk as precipitating factor was the fact that some studies
showed slightly increased risk of MS, though not to a statistically
significant degree. Evidence against was that another study
showed no increased risk. The group concluded that the
evidence for an association between the hepatitis B vaccine
and MS was weak, and did not meet the criterion for causality.
Response to this data has shown a rare divergence in public
health policies. The French National Network of Public
Health, while still recommending the vaccine as useful to
pre-adolescents, concluded that, because of differences in
individual risk for hepatitis B and for side effects of the
vaccine and "the need for a medical consultation including the
personal and family history," the vaccination program for
pre-teens in the schools would be suspended. This suspension
was announced on October 1, 1998. Public health departments
in several other countries, along with the World Health
Organization, criticized the French government for making
a decision based more on politics than on the actual risks,
and reaffirmed existing vaccination policies. The US Congress
held hearings on the subject, while the CDC affirmed that
"The scientific evidence to date does not support hepatitis B
vaccination causing MS or other demyelinating diseases."
(http://www.cdc.gov/nip/vacsafe/fs/qhepb.htm#7)
Several organizations concerned with hepatitis B and multiple
sclerosis, in the US and Canada, came out with statements
supporting continued hepatitis B vaccination.
As I write this section of the FAQ, the CDC reports that at
least six research projects are underway, in the US, France,
and the UK, to examine what relationship, if any, exists
between the hepatitis B vaccine and multiple sclerosis. In
the meantime, most countries are continuing to recommend
universal hepatitis B vaccination for infants and for pre-teens
who have not already been vaccinated.
Q3e.9 When is the hepatitis B vaccine contraindicated?
Sensitivity to yeast or any other component of the vaccine.
Pregnancy is not a contraindication to hepatitis B vaccination.
A previous anaphylactic response to the vaccine is a
contraindication to further doses.
Vaccine components capable of causing adverse reactions: aluminum
phosphate, thimerosal, and formaldehyde (Travel Medicine Advisor).
(Note, though, that as of September 1999, a thimerosal free
hepatitis B vaccine is available.)
Q3e.10 Why did the ACIP and AAP change their recommendation about the
hepatitis B vaccine?
Up until 1992, the recommendation was that hepatitis B vaccine be given
only to people in high risk groups for hepatitis B: people whose
professions exposed them to blood, people at extra risk due to their
sexual practices or intravenous drug use, and certain populations (such
as Southeast Asian immigrants) with a high incidence of the disease. The
chief reason was cost; it was felt to be not cost-effective to vaccinate
low-risk groups.
Unfortunately, this policy was not successful in checking the spread of
hepatitis B. It proved difficult to identify high-risk people, and
high-risk people did not volunteer in large numbers to be vaccinated.
For this reason, in 1992, the ACIP recommendation was switched to
vaccination of teens and adults in high-risk groups and universal
vaccination of infants. The AAP made a similar recommendation but would
also like to extend hepatitis B vaccination to all adolescents, if possible.
The American Liver Foundation also supports hepatitis B vaccination of
infants, and their pamphlet on the subject suggests a variety of ways
in which even young children could come in contact with the virus (through
contact with blood, etc.). Though young children are at low risk of
catching hepatitis B, their risk of developing the chronic form of the
disease if they do catch it is higher than for adults.
The new policy was well-received internationally, and 30 countries now
have universal infant HBV vaccination programs. Many physicians remain
skeptical, however, and a survey in North Carolina showed one third of
pediatricians and <20% of family physicians supporting the new guidelines
(Journal Watch, 9-1-93). (Update: Journal Watch for Jan 15, 1995/Feb 7,
1995 reports that this vaccine is gaining physician acceptance, citing
Arch Pediatr Adolesc Med Sep 1994, p. 936)
Why the resistance? One reason is a reluctance to give low-risk infants
yet another vaccination. Another is doubt about the duration of HBV
vaccine. There is evidence that it lasts up to 10 years, but we do not
know yet whether it wears off beyond that point. There is concern that
infants vaccinated for HBV may lose immunity during adolescence, when the
risk of catching the disease is greatest. An alternative would be to
vaccinate all children at age 10 and give a booster at age 20. But
compliance would likely be lower at age 10 than in infancy. Hepatitis B
vaccine is administered in three shots over the course of six months, and
it would be difficult to get preteens to all come in for the full series.
Also, 8% of hepatitis B infections occur before age 10, and the deadly
form is three times greater in children (NY Times, 3/3/93:B8). Boosters
could be given later to infants vaccinated for HBV if immunity proves to
lapse.
Hepatitis B vaccine is also often recommended for travel purposes.
Q3e.11 Does vaccination for hepatitis B affect one's ability to
donate blood?
It is still useful to be vaccinated, because some of the people who show
up positive on the blood bank tests are false positive.
Q3e.13 I will be travelling to an area where hepatitis B shots are
recommended, but I have less than six months before I leave. Is there
an accelerated schedule for hepatitis B vaccination?
_Travel Medicine Advisor_ lists an accelerated schedule, with 3 doses
at 0, 30, and 60 days. With this schedule, a fourth dose is recommended
at 12 months if there is still a risk for hepatitis B exposure.
Section 1 of the misc.kids Childhood Vaccinations FAQ
*************************************************************************
From J Thompson (jet14@columbia.edu):
The tetanus vaccine is actually against the tetanus toxin (a protein
called tetanospasmin), rather than the bacterium alone. The bacterium
doesn't really do much of significance, but the toxin it secretes can cause
muscular spasms. Thus, antibiotic therapy is rather pointless in preventing
the spasms, but it is given anyway. The administration of antitoxin (passive
immunity) is helpful. (see Harrison's, 13th ed., p. 635)
The vaccine consists of what is called "tetanus toxoid," which is simply
a purified version of the toxin, which has been treated to render it
ineffective as a toxin (but still immunogenic).
*************************************************************************
Q3a.10 How common was tetanus before routine vaccination, and how
common is it now?
From Mike Dedek:
*************************************************************************
American Journal of Diseases of Children 1992; 146: 173-176, February 1992,
"Pertussis outbreaks in Groups Claiming Religious Exemptions to Vaccinations",
Etkind, Lett, et. al.:
Q3a.14 Did SIDS disappear in Japan after the Japanese changed their
pertussis vaccination policy in 1975?
From Mike Dedek:
This next one indicates there's a better vaccine that may soon become
available [Note: this vaccine is now available, and recommended for
all doses in the US and some industrialized countries]:
*************************************************************************
In Pediatrics 1992; 89; 882-887, May 1992, "Acellular Pertussis Vaccination
of 2-Month Old Infants in the United States", Pichichero, Francis, et. at.:
ABSTRACT: This is the first study in children from the United States that
evaluates the immunogenicity of and adverse reactions to the Connaught/Biken
two-component acellular pertussis vaccine compared with whole-cell pertussis
vaccine when given as a primary immunization series at 2, 4, and 6 months of
age. Three hundred eighty infants were studied; 285 received acellular
diphtheria-tetanus toxoids- pertussis (DTP (ADTP)) and 95 received whole-cell
DTP (WDTP). Following the third dose, ADTP vaccination produced higher antibody
responses than WDTP to lymphocytosis-promoting factor (enzyme-linked
immunosorbent assay IgG geometric mean titer (GMT) = 131 vs 9 and Chinese
hamster ovary cell assay GMT = 273 vs 16) and to filamentous hemagglutinin (IgG
GMT = 73 vs 10) (all P < .0001). Agglutinin responses were higher in WDTP
compared with ADTP recipients (GMT = 50 vs 37; P = .02). Local reactions were
fewer for all three doses following ADTP vaccination. Fever, irritability,
drowsiness, anorexia, vomiting, and unusual crying all occurred less frequently
in ADTP compared with WDTP recipients for one or more of the three doses. We
conclude that this two-component ADTP vaccine when given as a primary series
produces greater immunogenicity and fewer adverse effects than the currently
licensed WDTP vaccine.
...A large case-control study
in Britain (National Childhood Encephalopathy Study) estimated that permanent
neurologic deficits may occur after its administration in 1 in 310000 doses
of WDTP. However, a reanalysis of this and similar studies recently has led
to the widely held conclusion that a causal association between WDTP vaccination
and permanent brain damage has not been demonstrated....
*************************************************************************
Public Health Rep 1992; 107: 365-366, May 1992/June 1992, "FDA Approves New
Whooping Cough Vaccine"
The Food and Drug Administration (FDA) has licensed a new whooping cough
vaccine that may cause fewer side effects in children.
The new vaccine is being approved at this time only for the fourth and
fifth shots. The current vaccine will continue to be used for the first three
shots. Additional research has been undertaken to ascertain whether it will be
effective for preventing pertussis when used for primary inmunization -- the
first three shots -- in infants.
The new vaccine is acellular, meaning that it is made from only part of the
pertussis organism, as opposed to the whole organism from which the current
vaccine is derived.
Whooping cough ( pertussis) is a highly contagious disease. As many as 90
percent of nonimmune household contacts acquire the infection. Since routine
immunization against pertussis became common in the United States, the number
of reported cases of disease and deaths from it has declined from about 120,000
cases with 1,100 deaths in 1950 to an annual average in recent years of about
3,500 cases with 10 fatalities.
The new vaccine appears to be as effective in older children as the current
vaccine and to cause fewer adverse reactions. It has been widely used in Japan
-- where it was developed -- with apparent success in children older than 2
years. It will be combined with diphtheria and tetanus toxoids (DTP) and sold
under the brand name Acel-Imune.
Gerald Quinnan, MD, acting director of FDA's Center for Biologics, where the
vaccine was evaluated and licensed, said that the availability of an acellular
vaccine is a significant step forward in infectious disease control.
The most common adverse reactions seen in clinical trials of the acellular
pertussis vaccine included tenderness, redness, and swelling at the injection
site, fever, drowsiness, fretfulness, and vomiting.
The new pertussis vaccine component is produced by Takeda Chemical
Industries Ltd. of Osaka, Japan, and is combined with diphtheria and tetanus
toxoids manufactured by Lederle Laboratories of Wayne, NJ. Lederle will also
distribute the product in the United States. The vaccine is administered by
injection.
The approval of the new vaccine comes at a time when the Federal Government
is emphasizing early childhood immunizations in the wake of the largest reported
measles outbreak in the nation in 20 years -- with more than 27,600 cases and 89
deaths reported in 1990.
The aim is to reach a goal of full immunization for 90 percent of children by
the time they are 2 years old.
*************************************************************************
As of September 1999, results are available from still more studies.
Since 1991, seven studies in Europe and Africa evaluated the efficacy of
eight DTaP vaccines given to infants. The vaccines were by different
manufacturers, with varying number and quantity of antigens. Number of
doses varied (three in some, four in others), as did other aspects of
the study design, such as the case definition for pertussis and the
laboratory method used to confirm the diagnosis. For this reason, the studies
can't be compared directly, but within the individual studies, the efficacy
of whole cell vaccine can be compared with the efficacy of acellular.
Acellular was within the range expected for whole cell. Estimates of
efficacy ranged from 59% to 89%. More serious adverse effects (fever over
105 F, persistent crying for more than three hours, hypotonic hyporesponsive
episodes, and seizures) happened less often with acellular. Really rare
adverse events (encephalopathy and anaphylactic shock) were too rare to
show up in these studies. Acellular pertussis vaccines have also been
used routinely since 1981 in Japan.
Section 3b. Polio
[This section last updated September 19, 1999.]
*************************************************************************
From Caren Feldman:
> Speaking of this, I know there has been mention in the past of contracting
> polio from handling diapers of recently immunized infants. Does anyone
> know how long after receiving the vaccine the child's excrement continues to
> contain the virus? The reason I ask is because sean got his polio booster
> and Rachel has only received the first vaccine in the series. The doctor's
> office said she wain no danger of contracting poliofrom him since they don't
> come in contact with each other *that* closely. However, I have to be extra
> careful after helping Sean clean up (he needs help sometimes) or handling his
> underwear to make sure I wash my hands thoroughly. So, how long until I
> can stop being paranoid about remembering to wash my hands after handling
> the laundry? (I forgot to ask)
>
The short answer is 6 weeks. But since you brought up the subject...here's what
I fond out about polio immunizations:
When I had read one poster's response that the live polio virus from feces
was actually weakened virus that would in fact help immunize unimmunized kids
they'd come in contact with it, naturally I didn't believe it. Well, not at
first. But I had enough doubts of my disbelief to start asking around, and came
up with some (at least to me) little known facts about polio and polio
immunizations. I am presenting it to misc.kids for everyone's edification.
Indeed, live virus from a recently immunized child's feces is weakened virus
that health officials actually hope unimmunized kids come in contact with to
provide them with individual immunity and the general population with "herd"
immunity.
Now here's the tricky part. One of the attenuated strains used to make the
vaccine has a very low but existing back mutation rate, back to the "wild
type", i.e. back to "regular" polio. If the weakened virus the child has been
given mutates back to wild-type polio, any adult with no immunity to it (or
an immunized adult for whom the immunization series did not "take") is
potentially at risk for full blown polio. Of course, people with weak immune
systems may be at risk even from weakened virus. Steroid use may also cause
the immune system to weaken (besides the usual anti-rejection drugs, HIV,
leukemia) and thus increase susceptibility for contracting the virus.
Polio in young children manifests itself as a mild gastrointestinal ailment.
Polio in older children and adults starts as a mild gastroenteritis but with
complications that may lead to paralysis. Before the advent of improved public
sanitation, most young children were exposed to and probably contracted the
polio virus, so by adulthood, chances were everyone had immunity to it. It
was only when public sanitation improved to where exposure to the virus was
delayed until later childhood that polio epidemics became prevelant. Polio
outbreaks in the US were less frequent among poor children than among more
affluent families.
The CDC estimates the chances of getting polio from a first immunization (I
presume this means gastroenteritis symptoms in babies, not paralytic polio)
is one in half million. The chances of getting polio from subsequent
immunizations is 1 in 12 million. I assume the chances of secondarily
contracting polio from feces are even rarer.
These rare cases probably account for the supermarket tabloid (not to mention
"60 Minutes") stories of adults catching polio from recently immunized kids
who'd been given oral vaccine. For those in the US, you will be glad to
hear that a federal compensation program exists, called the National Vaccine
Injury Compensation Program, to help those stricken with paralytic polio as a
result of coming into contact with a recipient of the oral polio vaccine.
Thanks go to two posters on sci.med for answering my questions regarding this
subject.
*************************************************************************
The 1993 Physician's Desk Reference confirms Caren Feldman's account,
with two small modifications. First, it gives the time when the virus
is shed as 6-8 weeks, rather than six. Second, the CDC estimates which
she gives are the estimates for cases of paralysis in *both* vaccine
recipients and contacts of vaccine recipients combined, not for recipients
alone.
From Mike Dedek:
*************************************************************************
>From The Reuter Library Report, 2/26/93, "U.N. Warns on need for Polio
Immunisation" copyright 1993 Reuters:
The last outbreak of polio took place in the Netherlands 15 years ago. The
virus was carried to Canada and the United States by infected people visiting
their relatives, the WHO said. This caused the United States' last polio
outbreak which hit the Amish community in the state of Pennsylvania in 1979.
*************************************************************************
>From The [London] Independent, 2/9/93, pg. 12, "Why child vaccines may be a
shot in the dark", by Tessa Thomas:
After numerous cases in which the ''live'' oral polio vaccination was
found to have caused the disease, the American government is considering
reintroducing the inactivated injectable version. In the UK, the Department of
Health advocates the live version on the basis that it deactivates any wild
polio virus that reaches the gut, preventing it being excreted into the
community, thus conferring community protection. The injectable vaccine acts
only on the bloodstream, protecting the individual but not breaking the chain of
infection. Lobbying by the Association of Parents of Vaccine Damaged Children
has prompted an acknowledgement by Virginia Bottomley, the Secretary of State
for Health, that the live vaccine is responsible for 50 per cent of recent new
cases of polio. Between 1978 and 1991 there were 42 cases of polio, 18 of
which followed vaccination and nine of which followed infection through contact
with the vaccinated child.
*************************************************************************
The Atlanta Journal and Constitution, 12/19/92, "Cases in Netherlands put
Americas at risk for polio", by Steve Sternberg, Section E; pg. 1
The last polio case in the Americas emerged on Aug. 23, 1991 in the remote
Peruvian highlands village of Pichinaki...
*************************************************************************
UPI 12/10/92:
Except for a few rare vaccine-associated cases, there have been no cases
of polio in the United States since 1986 when there was one imported case.
The current vaccine, Sutter said, is close to 100 percent effective in
preventing the disease.
*************************************************************************
MMWR's Summary of Notifiable Diseases, United States, 1997 (MMWR, November
20, 1998 / 46(54);1-87) reports that "Since 1980, a total of 147 cases have
been reported, of which 139 were associated with the use of OPV. The last
imported case was reported in 1993."
Section 3c. MMR (measles, mumps, and rubella)
[This section last updated on October 23, 1999.]
*************************************************************************
From Anthony C.:
I havent finished reading this thread so pardon if someone else has
already posted this information
Rates of complications of measles and measles immunization
Measles per 10^5 Vaccine per 10^5
Encephalomylelitis 50-400 .1
sspe .5-2.0 .05-.1
Pneumonia 3800-1000
Seizures 500-1000 .02-19
Deaths 10-10000 .01
These statistics are worldwide, hence the variablility in numbers. The
higher rates of pneumonia and death represent figures collected from
India, Nambia, Nigeria, bangladesh and other countries with developing
health care industries.
As far as the number of people afflicted with measles in the US
Cases Deaths
1963 385,566 364 Inactivated measles type vaccine available
1964 458,093 421
1966 204,136 261 public health administration of vaccine
1967 62,705 81
1968 22,231 24
.
.hovers around 20-70,000
.
1977 57,345 15
1978 26,871 11
1979 13,597 6
1980 13,506 11
1981 3,032 2
1982 1,697 2
1983 1,497 4
1984 2,587 1
1985 2,822 4
1986 6,273 2
1987 3,588 2
1988 2,933 not available
1989 16,236 41
1990 26,520 97
iMajor foci of retransmission barring the complete elimination of measles:
1) unimmunized indigent, inner city youngsters.
2) illegal aliens.
I hope this is useful. My source is Zinsser microbiology, 20th edition
pages 1013-1015, joklik et al.
*************************************************************************
As the above table shows, there was a marked increase in
measles incidence in the US from 1989 to 1991. This resulted
in more than 50,000 cases including 125 deaths
(http://www.immunize.org/nslt.d/n21/paradx21.htm).
Measles has been on the decline again in the US since 1990 (MMWR Feb 4,
1994, p. 57). Colleges enforcing the requirement for a second measles
vaccine report fewer measles outbreaks than schools with no requirement
(JAMA, Oct 12, 1994, p. 1127). (Both of these citations from Journal
Watch for Jan 15, 1995 - paper edition, or Feb 7, 1995 - electronic
edition.) During 1998, a provisional total of 100 measles
cases was reported to the CDC, making for a record low,
28% lower than the 138 cases reported in 1997 (MMWR 48(34);749-753,
1999. Centers for Disease Control).
Another reference, from Heather Madrone:
*************************************************************************
D. M. Horstmann "Controlling Rubella: Problems and Perspectives"
_Annals of Internal Medicine_, vol. 83, no. 3, pg. 412
Horstmann found reduced antibody formation 3-5 years after administering
the vaccine and 25% of those tested showed no immunity to rubella at
all.
*************************************************************************
Q3c.15 What are the pros and cons of vaccinating all infants for
rubella versus vaccinating females only at puberty?
Section 3d. HiB (Hemophilus influenze B)
[This section last updated September 19, 1999.]
Section 3e. Hepatitis B gamma globulin and hepatitis B vaccine
[This section last updated on September 15, 1999.]
American Liver Foundation
1425 Pompton Avenue
Cedar Grove, NJ 07009
A source on hepatitis B in particular is:
Hepatitis B Coalition
1537 Selby Ave #229
St Paul, MN 55104
(612) 647-9009
There is also a hepatitis mailing list, HEPV-L on LISTSERV@SJUVM.STJOHNS.EDU.
A Web page on Diseases of the Liver can be found at
Hepatitis Branch
Mailstop G37
CDC
Atlanta, GA 30333
or call the CDC Automated Voice Information System at (404) 332-2553.
Hepatitis B should not be confused with hepatitis A, which is more
contagious but less serious. Hepatitis A is spread through contaminated
food and water. Symptoms can be mild flulike symptoms or severe nausea
lasting for weeks. Hepatitis A does not become chronic and is rarely
fatal. Other forms of hepatitis include hepatitis C, hepatitis D, and
hepatitis E, and hepatitis (being a general term for inflammation of
the liver) can also be caused by certain medications. Information on
other kinds of hepatitis can be obtained from the American Liver
Foundation.
*************************************************************************
From Gregory Froehlich, MD (from a posting to sci.med):
First, hepatitis B *antigen* is used to make Hep B vaccine. The
antigen is grown in yeast culture; formerly, it was purified from the
blood of people who were chronic hepatitis carriers. Antibodies are
used in the gamma globulin shots used for hepatitis A or for passive
immunization against hepatitis B if you're exposed.
The local blood bank does not specifically test for exposure to
hepatitis A (the kind you'd get from contaminated water). If a person
has an active hep A infection, it will be picked up by elevated liver
enzymes; if the person had such an infection in the past, it's over and
done with--hep A doesn't give you a chronic, subclinical infection.
Antibodies to hepatitis A should not preclude blood donation.
They check for chronic hep B carriers by testing for hep B surface
antigen. They test for recent hep B infection by testing for hep B
core antibody. This antibody does not carry disease, but rather
indicates that the person was recently infected and might or might not
still be infectious. They do not test for surface *antibody*, which
would indicate either (a) former hep B infection which was cleared, or
(b) immunization against hep B--in either case, not infectious. I've
got hep B surface antibody, because I was immunized; I can still donate
blood.
Blood banks also test for hepatitis C antibody; people with this
antibody can still be infectious.
*************************************************************************
Q3e.12 Do people who have showed up positive on the blood banks' tests
for hepatitis B exposure still need to be vaccinated?
Section 3 of the misc.kids Childhood Vaccinations FAQ
Section 4 of the misc.kids Childhood Vaccinations FAQ
Back to the Childhood Vaccinations page of the Children's Health page