Can immunization affect the
development of allergy?
Pershagen
G.
Institute of Environmental Medicine, Karolinska
Institutet, Stockholm, Sweden.
A changing pattern of infections
may be of importance for the increase in prevalence of asthma and other
allergic diseases in developed countries during recent decades. The
clear inverse relation between number of siblings and atopy observed in
several studies may be related to a protective role of infections,
although specific information is inconclusive. A recent study showed
that positive tuberculin responses in schoolchildren correlated with a
lower prevalence of atopic disorders, but other studies did not find a
relation between BCG vaccination and allergic disease or sensitization.
Transient production of IgE antibodies to pertussis toxin has been
demonstrated after pertussis immunization; however, randomized clinical
trials involving both whole cell and acellular pertussis vaccines have
failed to show any enhancement of atopic manifestations in children.
Epidemiologic investigations indicate that viral infections may either
promote (RSV) or inhibit (hepatitis A, measles) atopy, although data are
scarce. In conclusion, the evidence is limited regarding a direct role
of vaccinations for development of atopic manifestations, but speaks
against a major effect of some types of vaccinations. On the other hand,
since some infections may offer protection in relation to allergy,
vaccination could result in an increased risk.