Evidence that multiple vaccinations during deployment are to blame is inconclusive
- Seif Shaheen, senior lecturer in clinical epidemiology (email@example.com)
- Department of Public Health Sciences, Guy's, King's and St Thomas's School of Medicine, King's College, London SE1 3QD
Papers p 1363
Vaccinations could have long term, non-specific effects on immune responses in children and adults, some undesirable, others beneficial. For example, there has been speculation that vaccines could influence the development of atopy. We have known for years that the pertussis vaccine is an adjuvant for IgE production, and conjecture that vaccinations might have contributed to the rise in atopic disease in children was an inevitable corollary of the “hygiene hypothesis.” 1 This hypothesis proposes that the prevalence of atopy has increased because infections in early life protect against atopy and children have been less exposed to infections over time. The discovery of polarised T helper cell responses, Th1 and Th2, fuelled the debate.2 It led to a theoretical model whereby the development of atopy characterised by Th2-type cytokine responses to allergens and production of IgE might be promoted by vaccines that induce Th2 cytokines or inhibited by those that induce Th1 cytokines.
However, evidence from observational studies that vaccinations increase the risk of atopy is contradictory, and early follow up of a cohort from a trial of pertussis vaccine suggests that this vaccine, at least, is unlikely to be an important cause of atopic disease.3 …