Vaccine Related Adverse Effects

Vaccines, although safe, may be associated with adverse events ranging in severity from mild to life threatening. Vaccine-related adverse events, however, are uncommon and typically mild. Vaccine components can cause local or systemic reactions, including anaphylaxis and urticaria, in some recipients. Some adverse events occur coincidentally in temporal association with vaccination and are not caused by the vaccine. Although determination of causality of an adverse event in a single child may be difficult, and epidemiologic studies are necessary to ascertain the incidence and nature of adverse reactions to vaccines, when a child is brought to hospital to be evaluated for a condition, the doctor may be called upon to determine the likelihood that it was caused by a recently administered vaccine. This determination has substantial implications for medical care, including the safety of administering future vaccines. Using the information on the current understanding of vaccine related adverse events reviewed by this article, doctors should be able to identify those events likely to be related to vaccine administration.