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Vaccines and Autism
CDC:
Vaccines and Autism
Facts
About Autism
Autism
Fact Sheet
What
is Autism?
MMR
Vaccine and Autism
CDC�s
Autism Research Efforts
Inflammatory
Bowel Disease (IBD) and Vaccines
References
and Other Resources
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Rotavirus Vaccine
CDC recommends that healthcare providers and parents postpone use
of the rotavirus vaccine for infants, at least until November 1999,
based on early surveillance reports of intussusception (a type of
bowel obstruction that occurs when the bowel fold in on itself)
among some infants who received rotavirus vaccine.
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Thimerosal
in Vaccines
Thimerosal-Containing Vaccines and Neurodevelopmental Disorders.
Report by the Institute of Medicine's Immunization Safety Review:
Historical Information:
-
Notice
to Readers: Update: Expanded Availability of Thimerosal Preservative
- Free Hepatitis B Vaccine MMWR, July 21, 2000
-
Notice
to Readers: Summary of the Joint Statement on Thimerosal in
Vaccines MMWR, July 14, 2000
-
Recommendations
Regarding the Use of Vaccines That Contain Thimerosal as a Preservative
MMWR, November 5, 1999
-
Hepatitis
B Vaccine without Thimerosal is Licensed by FDA MMWR,
September 10, 1999
-
Joint Statement of the American
Academy of Pediatrics and the U.S. Public Health Service
- July 7, 1999
-
Statement
by David Satcher, M.D., Ph.D., U.S. Surgeon General, Assistant
Secretary for Health, HHS
Other Resources:
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The
safety record on vaccines
Vaccines are
very safe. Today, the United States has the safest, most effective
vaccine supply in history. Vaccines have provided Americans with
tremendous health benefits, with a minimum of risk. In 1996, almost
81.6 million immunizations
were given in the U.S. alone, and many billions more have been given
safely around the world.
The prosperity of any nation is directly linked to the health of
its population. The widespread availability and acceptance of immunization
in America has prevented a huge burden of disease,
complications, and deaths from polio, measles, pertussis (whooping
cough), tetanus (lockjaw), diphtheria, mumps, and rubella ("German"
measles). As recently as 1990, Haemophilus influenza type
b was a common, devastating illness and the leading cause of bacterial
meningitis in U.S. children. Now, most pediatricians (doctors who
specialize in diseases of childhood) just finishing their training
have never seen a case, thanks to immunizations.
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Vaccine
risks
As with any medical procedure or medication, immunizations
are associated with a risk of an adverse reaction. Typical reactions
may include warmth, redness, and tenderness at the site of the injection,
and irritability. Potential serious reactions vary according to
the type of immunization, and include the potential for seizures,
damage to the brain or central nervous system, and death. However,
most reactions are minor and treatable. There are so few deaths
that could plausibly be connected to vaccine, and the risk is so
small, that it is hard to assess statistically.(1)
The National Vaccine Program Office supports continuous vigilance,
so that any increase in risk from a vaccine is quickly recognized
and so that measures can be taken to make vaccines even safer. The
CDC National
Immunization Program and the Food
and Drug Administration (FDA) have systems in place for monitoring
reports of reactions. Among these is the Vaccine
Adverse Event Reporting System (VAERS) , which is described
more fully below in the section titled "How Vaccine Safety
Is Monitored."
Vaccines have been so successful in preventing disease in the U.S.
that in recent years, the annual number of reports to VAERS have
exceeded the total number of reports of routine childhood vaccine-preventable
disease. This may lead some people to believe that the vaccines
are dangerous. However, based on the very large numbers of data
collected nationwide through the various data systems, the risk
of a serious adverse reaction to an immunization is extremely small.
The risk of the disease itself is substantially more serious than
the risk of the immunization. The risks of specific vaccines
are posted on the CDC National Immunization Program home page, which
you can access by clicking
here.
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How
vaccine safety is tested
The U.S. government agency charged with assuring the safety of vaccines
in development, vaccines in clinical trials (experimental studies
that occur in phases, gradually increasing the number of people
involved in testing), and vaccines in use is the FDA.
In general, all vaccines must receive two licenses before being
released for marketing: one for the vaccine, and one for the manufacturing
plant. It is the FDA that defines the rigorous studies and many
documents required to get the license, as well as actually granting
or refusing a license. The FDA is also involved in the type of labeling
that is done and the information that is given to health care professionals
about how to use the vaccine, precautions, known side effects, and
other aspects of the vaccine. Once a license is granted, manufacturers
may begin producing the vaccine, but they must continuously test
each lot of the product for potency, safety, and quality, and the
results of these tests must be given to the FDA.
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How
vaccine safety is monitored
Once a vaccine is in use, physicians must keep very careful records
of who receives the vaccine and what lot of vaccine was used. This
way, if a problem arises, it is possible to track down the lot that
was used, so it can be tested and evaluated to see if the vaccine
was at fault.
Administering the vaccine is not the end of the monitoring process.
As described by the Institute
of Medicine in a 1997 workshop summary,(2)adverse
events that may be linked with vaccines are monitored in four ways:
1.The Vaccine Adverse Event Reporting System (VAERS).
The National Childhood Injury Act was established in 1986. This
law requires health care providers to report any serious adverse
events that occur within 30 days after vaccination
with any vaccine. The reports must be submitted to VAERS, which
was set up in 1990 and is managed by the Centers for Disease Control
and Prevention and the FDA. The VAERS system is capable of creating
clues that may be useful in uncovering potential new adverse events
and any change (increase or decrease) in the rate of reporting of
previously known adverse events associated with vaccines. However,
it is a "passive" system of gathering data, and therefore
may not capture as many events as an aggressive system would. More
important, since lot sizes vary and the number of doses within a
lot that have actually been given is not known, the raw number of
reported adverse events, by itself, does not make it possible to
interpret whether there is an actual problem. For example, "three
adverse events" may have entirely different meaning if a million
doses have been given, versus 30 doses. For additional in-depth
information on VAERS, click
here.
Patients, parents, or even non-relatives who witnessed or who are
aware of a reaction can also submit a report to VAERS. A copy of
the VAERS reporting form and instructions for how to submit it can
be obtained by calling 1-800-822-7967. You can also download and
print a copy of the form from the web site of the FDA. To access
that form, click
here
2. The Vaccine Safety Datalink (VSD). The VSD was
established by the CDC in 1990. It links large databases of four
health maintenance organizations containing data on a known population
size (more than 500,000 children of ages 0 to 6 years, both vaccinated
and not vaccinated), in Oregon, Washington, and California. Because
this system actively finds cases and systematically reviews medical
records from a population of known size, the VSD captures more complete
data on adverse events associated with vaccination. The VSD makes
it possible to do large epidemiologic studies of vaccine adverse
events, captures information on less commonly occurring types of
adverse events, and helps determine whether an event is linked with
a vaccine or with some other cause.
3. Surveillance by vaccine manufacturers. Manufacturers
are required by the National Childhood Vaccine Injury Act of 1986
to report adverse events to the Department of Health and Human Services.
(3)
4. Monitoring by the FDA. The FDA monitors adverse
events reporting rates, using both the VAERS data and manufacturers�
data. Among the things FDA looks for are large numbers of adverse
event reports early in the circulation of a lot, clusters of similar
cases, syndromes (groups of symptoms), or other patterns; additional
information from other sources with knowledge of a particular case;
patterns of reported adverse events linked to final lots filled
from the same bulk vaccine; and documentation that lots in question
have passed all the required tests.
The VSD and VAERS are complementary methods of monitoring data.
VAERS is a signal generator, designed to provide clues that there
may be problems with specific lots of vaccine that require more
investigation. VSD provides actual incidence rate of diseases and
events that occur around the time of vaccination and at times not
linked to vaccination, making it possible to evaluate whether the
vaccine actually caused the adverse event and, if so, the magnitude
of the problem.
Information about the concept of a national vaccination registry
will be posted on this site in the future.
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Parents
have a role in vaccine safety, too
Government agencies and vaccine manufacturers have strict guidelines
for vaccine safety, but a parent plays a role, too. Here are several
things a parent can do:
1.If any aspect of your child�s appearance or behavior gives you
concern after a vaccination, report it to your child�s health care
provider immediately. Respond to your instincts as a parent. If
you feel the situation is an emergency, say so. Write down what
happened and the date and time it happened. Ask your health care
provider to file a Vaccine Adverse Event Report form or call 1-800-338-2382.
2.Learn the facts about immunizations and infectious diseases. In
1993, a Gallup poll of 1,000 parents of children under five years
of age showed a great gap in many parents� understanding of immunization
and infectious diseases: 47% were unaware that polio is contagious,
36% didn�t know that measles can be fatal, and 44% didn�t know that
Haemophilus influenzae type b was the leading cause of potentially
fatal bacterial meningitis, a disease that as recently as 1985 was
a major killer of infants and toddlers. The section on Immunization
Concepts and the Quick Definitions of
Immunization Terms in this site provide a quick, basic course
on immunization. The Ten Tips on Evaluating
Information on Immunization, which follows this section, can
help you sort through information from various sources. The CDC
National Immunization Program web site has a wealth of information,
including information by specific immunizations. Click
here to go to the Question and Answer section of that site.
3.Periodically review the Current Vaccines and Recommended Vaccination
Schedule, which is posted in the "What�s
New?" section of the CDC National Immunization Program�s
web site. Vaccination schedules are available for adults
or children.
By following the schedule, you can be sure to get your child�s
immunizations at the safest and most advantageous age.
4.Always keep a record of your child�s immunizations, and
bring it with you to office visits. This will ensure that vaccines
are given on schedule and that your child does not receive excess
immunizations. This is especially important if you move, change
doctors, or vaccinations are given anywhere other than in your regular
physician�s office (for example, if your child is given a tetanus
[lockjaw] shot during an emergency room visit).
5. Review the Standards
for Pediatric Immunization Practice, which provides guidelines
on what your pediatrician or family health care provider should
know and do about vaccines.
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In
the rare event that something goes wrong: The National Vaccine Injury
Compensation Program (VICP)
The National Childhood Vaccine Injury Act of 1986 established the VICP. This program went into effect in October 1988 and is a Federal "no-fault" system designed to compensate those individuals, or families of individuals, who have been injured by childhood vaccines, whether administered in the public or private sector. The act covers the following vaccines: diphtheria, tetanus, pertussis (DTP, DTaP, DT, TT, or Td), measles, mumps, rubella (MMR or any components), polio (OPV or IPV), Haemophilus influenzae type b (Hib), rotavirus (RV), hepatitis A (HAV), hepatitis B (HBV), meningococcal (MCV4 or MPSV4), pneumococcal conjugate (PCV7), human papillomavirus (HPV), influenza (TIV or LAIV) and varicella (chicken pox) (VZV). While the act was written with vaccine-injured children in mind, it also applies to any adult who is injured by the vaccines listed above. Complete information on this program is available at the Health Resources and Services Administration website: http://www.hrsa.gov/vaccinecompensation/.
*For additional information on vaccine safety, go to the Questions
and Answers section of this site
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Footnotes
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1. Centers for Disease
Control and Prevention. What you may have heard about vaccines...and
what you should know [fact sheet]. Atlanta: CDC, Office of Communications,
1997:1.
2. Institute of Medicine, Vaccine Safety Forum,
Board on Health Promotion and Disease Prevention. Vaccine Safety
Forum: Summaries of Two Workshops. Washington DC: National Academy
Press, 1997.
3. Food and Drug Administration, Center for Biologics
Evaluation and Research. Vaccine adverse event reporting system
[online]. Washington, DC: FDA, 1997. Available at http://www.fda.gov. |
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