Introduction
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. Following are six misconceptions that appear in literature
about vaccination, along with explanations of why they are
misconceptions.
1.
Diseases had already begun to disappear before vaccines were introduced,
because of better hygiene and sanitation
2.
The majority of people who get disease have been vaccinated
3.
There are "hot lots" of vaccine that have been associated with
more adverse events and deaths than others
4.
Vaccines cause many harmful side effects, illnesses, and even death
5.
Vaccine-preventable diseases have been virtually eliminated from the
Unites States
6.
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.
1.
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 1920 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 unti
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.
2. 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.
3. 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.
4. 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 non-immunized 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 vs. Risk from Vaccines
|
DISEASE
|
VACCINES
|
Measles
Pneumonia:
1 in 20
Encephalitis: 1 in 2,000
Death: 1 in 3,000
Mumps
Encephalitis: 1 in 300
Rubella
Congenital Rubella Syndrome: 1 in 4
(if woman becomes infected
early in pregnancy)
|
MMR
Encephalitis
or severe allergic reaction:
1 in 1,000,000
|
Diphtheria
Death: 1
in 20
Tetanus
Death: 3 in 100
Pertussis
Pneumonia: 1 in 8
Encephalitis: 1 in 20
Death: 1 in 200
|
DTP
Continuous
crying, then full recovery: 1 in 100
Convulsions or shock, then full recovery:
1 in 1,750
Acute encephalopathy: 0-10.5 in 1,000,000
Death: None proven
|
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.
5.
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.
6.
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.
