Publications
Six Common Misconceptions
about
vaccination and how to respond to them
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A
great deal of information about vaccinations
is available to parents. This is good,
because parents should have access to any
information that will help them make informed
decisions about vaccination. However, information
is sometimes published that is inaccurate
or can be misleading when taken out of
context. |
Click
image to see enlarged version. |
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Following are six misconceptions that appear
in literature about vaccination, along with
explanations of why they are misconceptions.
-
Diseases
had already begun to disappear before vaccines
were introduced, because of better hygiene
and sanitation.
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The
majority of people who get a disease have
been vaccinated.
-
There
are "hot lots" of vaccine that
have been associated with more adverse
events and deaths than others.
-
Vaccines
cause many harmful side effects, illnesses,
and even death.
-
Vaccine-preventable
diseases have been virtually eliminated
from the United States.
-
Giving
a child multiple vaccinations for different
diseases at the same time increases the
risk of harmful side effects and can overload
the immune system.
Introduction
As
a practitioner giving vaccinations, you will
encounter patients who have reservations about
getting vaccinations for themselves or their
children. There can be many reasons for fear
of or opposition to vaccination. Some people
have religious or philosophic objections. Some
see mandatory vaccination as interference by
the government into what they believe should
be a personal choice. Others are concerned
about the safety or efficacy of vaccines, or
may believe that vaccine-preventable diseases
do not pose a serious health risk.
A practitioner
has a responsibility to listen to and try to
understand a patient's concerns, fears, and
beliefs about vaccination and to take them
into consideration when offering vaccines.
These efforts will not only help to strengthen
the bond of trust between you and the patient
but will also help you decide which, if any,
arguments might be most effective in persuading
these patients to accept vaccination.
The purpose
of this pamphlet is to address six common misconceptions
about vaccination that are often cited by concerned
parents as reasons to question the wisdom of
vaccinating their children. If we can respond
with accurate rebuttals perhaps we can not
only ease their minds on these specific issues
but discourage them from accepting other anti-vaccine
"facts" at face value. Our goal is
not to browbeat parents into vaccinating, but
to make sure they have accurate information
with which to make an informed decision.
- Diseases
had already begun
to disappear before vaccines were introduced,
because of better hygiene and sanitation.
Statements
like this are very common in anti-vaccine literature,
the intent apparently being to suggest that
vaccines are not needed. Improved socioeconomic
conditions have undoubtedly had an indirect
impact on disease. Better nutrition, not to
mention the development of antibiotics and
other treatments, have increased survival rates
among the sick; less crowded living conditions
have reduced disease transmission; and lower
birth rates have decreased the number of susceptible
household contacts. But looking at the actual
incidence of disease over the years can leave
little doubt of the significant direct
impact vaccines have had, even in modern times.
Here, for example, is a graph showing the reported
incidence of measles from 1950 to the present.
There
were periodic peaks and valleys throughout
the years, but the real, permanent drop coincided
with the licensure and wide use of measles
vaccine beginning in 1963. Graphs for other
vaccine-preventable diseases show a roughly
similar pattern, with all except hepatitis
B* showing a significant drop in
cases corresponding with the advent of vaccine
use. Are we expected to believe that better
sanitation caused incidence of each disease
to drop, just at the time a vaccine for that
disease was introduced?
*The
incidence rate of hepatitis B has not dropped
so dramatically yet because the infants we
began vaccinating in 1991 will not be at high
risk for the disease until they are at least
teenagers. We therefore expect about a 15 year
lag between the start of universal infant vaccination
and a significant drop in disease incidence.
Hib
vaccine is another good example, because Hib
disease was prevalent until just a few years
ago, when conjugate vaccines that can be used
for infants were finally developed. (The polysaccharide
vaccine previously available could not be used
for infants, in whom most of cases of the disease
were occurring.) Since sanitation is not better
now than it was in 1990, it is hard to attribute
the virtual disappearance of Hib disease in
children in recent years (from an estimated
20,000 cases a year to 1,419 cases in 1993,
and dropping) to anything other than the vaccine.
Varicella
can also be used to illustrate the point, since
modern sanitation has obviously not prevented
nearly 4 million cases each year in the United
States. If diseases were disappearing, we should
expect varicella to be disappearing along with
the rest of them. But nearly all children in
the United States get the disease today, just
as they did 20 years ago or 80 years ago. Based
on experience with the varicella vaccine in
studies before licensure, we can expect the
incidence of varicella to drop significantly
now that a vaccine has been licensed for the
United States.
Finally,
we can look at the experiences of several developed
countries after they let their immunization
levels drop. Three countries - Great Britain,
Sweden, and Japan - cut back the use of pertussis
vaccine because of fear about the vaccine.
The effect was dramatic and immediate. In Great
Britain, a drop in pertussis vaccination in
1974 was followed by an epidemic of more than
100,000 cases of pertussis and 36 deaths by
1978. In Japan, around the same time, a drop
in vaccination rates from 70% to 20%-40% led
to a jump in pertussis from 393 cases and no
deaths in 1974 to 13,000 cases and 41 deaths
in 1979. In Sweden, the annual incidence rate
of pertussis per 100,000 children 0-6 years
of age increased from 700 cases in 1981 to
3,200 in 1985. It seems clear from these experiences
that not only would diseases not be disappearing
without vaccines, but if we were to stop vaccinating,
they would come back.
Of
more immediate interest is the major epidemic
of diphtheria now occurring in the former Soviet
Union, where low primary immunization rates
for children and the lack of booster vaccinations
for adults have resulted in an increase from
839 cases in 1989 to nearly 50,000 cases and
1,700 deaths in 1994. There have already been
at least 20 imported cases in Europe and two
cases in U.S. citizens working in the former
Soviet Union.
Top
- The
majority of people who
get disease have been vaccinated.
This
is another argument frequently found in anti-vaccine
literature - the implication being that this
proves vaccines are not effective. In fact
it is true that in an outbreak those who have
been vaccinated often outnumber those who have
not - even with vaccines such as measles, which
we know to be about 98% effective when used
as recommended.
This
apparent paradox is explained by two factors.
First, no vaccine is 100% effective. To make
vaccines safer than the disease, the bacteria
or virus is killed or weakened (attenuated).
For reasons related to the individual, not
all vaccinated persons develop immunity. Most
routine childhood vaccines are effective for
85% to 95% of recipients. Second, in a country
such as the United States the people who have
been vaccinated vastly outnumber those who
have not. How these two factors work together
to result in outbreaks in which the majority
of cases have been vaccinated can be more easily
understood by looking at a hypothetical example:
In
a high school of 1,000 students, none has ever
had measles. All but 5 of the students have
had two doses of measles vaccine, and so are
fully immunized. The entire student body is
exposed to measles, and every susceptible student
becomes infected. The 5 unvaccinated students
will be infected, of course. But of the 995
who have been vaccinated, we would expect
several not to respond to the vaccine. The
efficacy rate for two doses of measles vaccine
can be as high as >99%. In this class, 7
students do not respond, and they, too, become
infected. Therefore 7 of 12, or about 58%,
of the cases occur in students who have been
fully vaccinated.
As
you can see, this doesn't prove the vaccine
didn't work - only that most of the children
in the class had been vaccinated, so those
who were vaccinated and did not respond outnumbered
those who had not been vaccinated. Looking
at it another way, 100% of the children who
had not been vaccinated got measles, compared
with less than 1% of those who had been vaccinated.
Measles vaccine protected most of the class;
if nobody in the class had been vaccinated,
there would probably have been 1,000 cases
of measles.
Top
- There
are "hot lots" of vaccine
that have been associated with more adverse
events and deaths than others. Parents should
find the numbers of these lots and not allow
their children to receive vaccines from them.
This
misconception got considerable publicity recently
when vaccine safety was the subject of a television
news program. First of all, the concept of
a "hot lot" of vaccine as it is used
in this context is wrong. It is based on the
presumption that the more reports to VAERS**
a vaccine lot is associated with, the more
dangerous the vaccine in that lot; and that
by consulting a list of the number of reports
per lot, a parent can identify vaccine lots
to avoid.
This is misleading
for two reasons:
A
report made to VAERS does not mean that the
vaccine, or other vaccines from the same group
or lot caused the event. VAERS is a national
system for reporting health problems that happen
around the same time of the vaccination. Only
some of the reported health conditions are
side effects related to vaccines. A certain
number of VAERS reports of serious illnesses
or death do occur by chance alone among persons
who have been recently vaccinated.
VAERS
reports have many limitations since they often
lack important information, such as laboratory
results, used to establish a true association
with the vaccine. For all serious and other
clinically significant events (life-threatening
events, hospitalization, permanent disability,
death), follow-up with the health care provider
and/or the parent or vaccinated individual
is conducted in an attempt to collect supplemental
information on the reports. Because of the
limitations of this type of reporting system,
causality is difficult to determine. Regardless
of the cause, VAERS is interested in hearing
about any health concerns that happen around
the time of vaccination. In summary, scientists
are not able to identify a problem with a vaccine
lot based on VAERS reports alone without scientific
analysis of other factors and data.
2.
Vaccine lots are not the same. The sizes of
vaccine lots might vary from several hundred
thousand doses to several million, and some
are in distribution much longer than others.
Naturally a larger lot or one that is in distribution
longer will be associated with more adverse
events, simply by chance. Also, more coincidental
deaths are associated with vaccines given in
infancy than later in childhood, since the
background death rates for children are highest
during the first year of life. So knowing that
lot A has been associated with x number of
adverse events while lot B has been associated
with y number would not necessarily say anything
about the relative safety of the two lots,
even if the vaccine did cause the events.
Reviewing
published lists of "hot lots" will
not help parents identify the best or worst
vaccines for their children. If the number
and type of VAERS reports for a particular
vaccine lot suggested that it was associated
with more serious adverse events or deaths
than are expected by chance, the Food and Drug
Administration (FDA) has the legal authority
to immediately recall that lot. To date, no
vaccine lot in the modern era has been found
to be unsafe on the basis of VAERS reports.
All
vaccine manufacturing facilities and vaccine
products are licensed by the FDA. In addition,
every vaccine lot is safety-tested by the manufacturer.
The results of these tests are reviewed by
FDA, who may repeat some of these tests as
an additional protective measure. FDA also
inspects vaccine-manufacturing facilities regularly
to ensure adherence to manufacturing procedures
and product-testing regulations, and reviews
the weekly VAERS reports for each lot searching
for unusual patterns. FDA would recall a lot
of vaccine at the first sign of problems. There
is no benefit to either the FDA or the manufacturer
in allowing unsafe vaccine to remain on the
market. The American public would not tolerate
vaccines if they did not have to conform to
the most rigorous safety standards. The mere
fact is that a vaccine lot still in distribution
says that the FDA considers it safe.
Top
- Vaccines
cause many
harmful side effects, illnesses, and even
death - not to mention possible long-term
effects we don't even know about.
Vaccines
are actually very safe, despite implications
to the contrary in many anti-vaccine publications
(which sometimes contain the number of reports
received by VAERS, and allow the reader to
infer that all of them represent genuine vaccine
side-effects). Most vaccine adverse events
are minor and temporary, such as a sore arm
or mild fever. These can often be controlled
by taking acetaminophen before or after vaccination.
More serious adverse events occur rarely (on
the order of one per thousands to one per millions
of doses), and some are so rare that risk cannot
be accurately assessed. As for vaccines causing
death, again so few deaths can plausibly be
attributed to vaccines that it is hard to assess
the risk statistically. Of all deaths reported
to VAERS between 1990 and 1992, only one is
believed to be even possibly associated with
a vaccine. Each death reported to VAERS is
thoroughly examined to ensure that it is not
related to a new vaccine-related problem, but
little or no evidence suggests that vaccines
have contributed to any of the reported deaths.
The Institute of Medicine in its 1994 report
states that the risk of death from vaccines
is "extraordinarily low."
DTP
Vaccine and SIDS
One
myth that won't seem to go away is that DTP
vaccine causes sudden infant death syndrome
(SIDS). This belief came about because a moderate
proportion of children who die of SIDS have
recently been vaccinated with DTP; and on the
surface, this seems to point toward a causal
connection. But this logic is faulty; you might
as well say that eating bread causes car crashes,
since most drivers who crash their cars could
probably be shown to have eaten bread within
the past 24 hours.
If
you consider that most SIDS deaths occur during
the age range when 3 shots of DTP are given,
you would expect DTP shots to precede a fair
number of SIDS deaths simply by chance. In
fact, when a number of well-controlled studies
were conducted during the 1980's, the investigators
found, nearly unanimously, that the number
of SIDS deaths temporally associated with DTP
vaccination was within the range expected to
occur by chance. In other words, the SIDS deaths
would have occurred even if no vaccinations
had been given. In fact, in several of the
studies children who had recently gotten a
DTP shot were less likely to get SIDS.
The Institute of Medicine reported that "all
controlled studies that have compared immunized
versus nonimmunized children have found either
no association . . . or a decreased risk .
. . of SIDS among immunized children"
and concluded that "the evidence does
not indicate a causal relation between [DTP]
vaccine and SIDS."
But
looking at risk alone is not enough - you must
always look at both risks and benefits. Even
one serious adverse effect in a million doses
of vaccine cannot be justified if there is
no benefit from the vaccination. If there were
no vaccines, there would be many more cases
of disease, and along with them, more serious
side effects and more deaths. For example,
according to an analysis of the benefit and
risk of DTP immunization, if we had no immunization
program in the United States, pertussis cases
could increase 71-fold and deaths due to pertussis
could increase 4-fold. Comparing the risk from
disease with the risk from the vaccines can
give us an idea of the benefits we get from
vaccinating our children.
Risk
from Disease versus Risk from Vaccines |
DISEASE
Measles
Pneumonia:
6 in 100
Encephalitis: 1 in 1,000
Death: 2 in 1,000
Rubella
Congenital
Rubella Syndrome: 1 in 4 (if woman
becomes infected early in pregnancy)
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VACCINES
MMR
Encephalitis
or severe allergic reaction:
1 in 1,000,000
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DISEASE
Diphtheria
Death:
1 in 20
Tetanus
Death:
2 in 10
Pertussis
Pneumonia:
1 in 8
Encephalitis: 1 in 20
Death: 1 in 200
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VACCINES
DTaP
Continuous
crying, then full recovery: 1 in
1000
Convulsions or shock, then full
recovery: 1 in 14,000
Acute encephalopathy: 0-10.5 in
1,000,000
Death: None proven
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The
fact is that a child is far more likely to
be seriously injured by one of these diseases
than by any vaccine. While any serious
injury or death caused by vaccines is too many,
it is also clear that the benefits of vaccination
greatly outweigh the slight risk, and that
many, many more injuries and deaths would occur
without vaccinations. In fact, to have a medical
intervention as effective as vaccination in
preventing disease and not use it would be
unconscionable.
Research
is underway by the U.S. Public Health Service
to better understand which vaccine adverse
events are truly caused by vaccines and how
to reduce even further the already low risk
of serious vaccine-related injury.
Top
- Vaccine-preventable
diseases
have been virtually eliminated from the United
States, so there is no need for my child
to be vaccinated.
It's
true that vaccination has enabled us to reduce
most vaccine-preventable diseases to very low
levels in the United States. However, some
of them are still quite prevalent - even epidemic
- in other parts of the world. Travelers can
unknowingly bring these diseases into the United
States, and if we were not protected by vaccinations
these diseases could quickly spread throughout
the population, causing epidemics here. At
the same time, the relatively few cases we
currently have in the U.S. could very quickly
become tens or hundreds of thousands of cases
without the protection we get from vaccines.
We
should still be vaccinated, then, for two reasons.
The first is to protect ourselves. Even if
we think our chances of getting any of these
diseases are small, the diseases still exist
and can still infect anyone who is not protected.
A few years ago in California a child who had
just entered school caught diphtheria and died.
He was the only unvaccinated pupil in his class.
The
second reason to get vaccinated is to protect
those around us. There is a small number of
people who cannot be vaccinated (because of
severe allergies to vaccine components, for
example), and a small percentage of people
don't respond to vaccines. These people are
susceptible to disease, and their only
hope of protection is that people around them
are immune and cannot pass disease along to
them. A successful vaccination program, like
a successful society, depends on the cooperation
of every individual to ensure the good of all.
We would think it irresponsible of a driver
to ignore all traffic regulations on the presumption
that other drivers will watch out for him or
her. In the same way we shouldn't rely on people
around us to stop the spread of disease; we,
too, must do what we can.
Top
- Giving
a child multiple vaccinations
for different diseases at the same time increases
the risk of harmful side effects and can
overload the immune system.
Children
are exposed to many foreign antigens every
day. Eating food introduces new bacteria into
the body, and numerous bacteria live in the
mouth and nose, exposing the immune system
to still more antigens. An upper respiratory
viral infection exposes a child to 4 - 10 antigens,
and a case of "strep throat" to 25
- 50. According to Adverse Events Associated
with Childhood Vaccines, a 1994 report
from the Institute of Medicine, "In the
face of these normal events, it seems unlikely
that the number of separate antigens contained
in childhood vaccines . . . would represent
an appreciable added burden on the immune system
that would be immunosuppressive." And,
indeed, available scientific data show that
simultaneous vaccination with multiple vaccines
has no adverse effect on the normal childhood
immune system.
A
number of studies have been conducted to examine
the effects of giving various combinations
of vaccines simultaneously. In fact, neither
the Advisory Committee on Immunization Practices
(ACIP) nor the American Academy of Pediatrics
(AAP) would recommend the simultaneous administration
of any vaccines until such studies showed the
combinations to be both safe and effective.
These studies have shown that the recommended
vaccines are as effective in combination as
they are individually, and that such combinations
carry no greater risk for adverse side effects.
Consequently, both the ACIP and AAP recommend
simultaneous administration of all routine
childhood vaccines when appropriate. Research
is under way to find ways to combine more antigens
in a single vaccine injection (for example,
MMR and chickenpox). This will provide all
the advantages of the individual vaccines,
but will require fewer shots.
There
are two practical factors in favor of giving
a child several vaccinations during the same
visit. First, we want to immunize children
as early as possible to give them protection
during the vulnerable early months of their
lives. This generally means giving inactivated
vaccines beginning at 2 months and live vaccines
at 12 months. The various vaccine doses thus
tend to fall due at the same time. Second,
giving several vaccinations at the same time
will mean fewer office visits for vaccinations,
which saves parents both time and money and
may be less traumatic for the child.
Reference:
Vaccines,
4th Edition
By Stanley A. Plotkin, MD and Walter A. Orenstein,
MD
Approx. 1696 pages, Copyright 2004
http://www.us.elsevierhealth.com/product.jsp?isbn=0721696880
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