Do early childhood
immunizations influence the development of atopy and do they cause
allergic reactions?
Gruber C, Nilsson L, Bjorksten
B.
Department of Pediatric Pneumology and Immunology, Charite
- Humboldt University, Berlin, Germany.
christoph.grueber@charite.de
Concerns about allergic side-effects
of vaccines and about a possible promotion of allergic diseases
contribute to incomplete vaccination rates in childhood. This article
reviews the current understanding of these issues. There is evidence
that pertussis and diphtheria/tetanus antigens elicit immunoglobulin E
(IgE) antibody formation as part of the immune response. In murine
models, pertussis toxin is an effective adjuvant for IgE formation
against simultaneously administered antigens. In children, however,
sensitization to unrelated antigens or development of allergic diseases
do not seem to be augmented. In contrast, bacille Calmette-Guerin (BCG)
and measles vaccination have been proposed as suppressors of allergy
because of their T helper 1 (Th1)-fostering properties. In the murine
system, BCG inhibits allergic sensitization and airway hyper-reactivity.
Some epidemiological studies in humans suggest an inhibitory effect of
tuberculosis on allergy. BCG vaccination in children, however, has no or
merely a marginal suppressive effect on atopy. Other vaccine components
such as egg proteins, gelatin, and antibiotics are a potential hazard to
children with severe clinical reactions to these allergens. These rare
children should be vaccinated under special precautions. In conclusion,
vaccination programs do not explain the increasing prevalence of
allergic diseases, but individual children may uncommonly develop an
allergic reaction to a vaccine. The risks of not vaccinating children,
however, far outweigh the risk for allergy. Therefore, childhood
vaccination remains an essential part of child health programs and
should not be withheld, even from children predisposed for
allergy.