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3a.13 What are some of the risks of the DTP vaccine?


This article is from the Childhood Vaccinations FAQ, by Lynn Gazis-Sax lynng@alsirat.com with numerous contributions by others.

3a.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

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.

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.:

2% non-vaccinated students are monitored>
Key measures in preventing pertussis are immunization and judicious
use of prophylactic antibiotics. Pertussis can be prevented in
children by immunization. Unfortunately, controversy over the safety
of the pertussis vaccine has reduced acceptance. Highly publicized
accounts of reactions to the vaccine and a dramatic increase in the
number of malpractice lawsuits have made physicians and parents wary
of using the diphtheria-tetanus toxoid and pertussis vaccine. {n4-n6}
This publicity may have caused overinterpretation of the guidelines
for medical contraindications. {n7} However, this overinterpretation
creates its own risk for malpractice if a child given an
inappropriate medical contraindication suffers damage due to disease.


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