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Adverse Events Associated with Childhood Vaccines: Evidence Bearing on Causality
The term anaphylaxis refers to the rapid onset (within 4 hours after vaccine administration) of a potentially life-threatening illness in which mortality is related either to cardiovascular collapse or to airway obstruction caused by either bronchospasm or laryngospasm. These life-threatening pathophysiologic events are often associated with cutaneous manifestations (hives, angioedema) and arthritis or arthralgias. Chapter 4 contains in-depth discussions of anaphylaxis and other adverse immunologic reactions, for example, the Arthus reaction and serum sickness, to vaccination.
History of Suspected Association
No infants or adults have been reported to have died of anaphylaxis after vaccination with either plasma-derived or recombinant hepatitis B vaccine. However, several cases of anaphylaxis following receipt of recombinant hepatitis B vaccines have been reported in adults. Of the groups of adults in industrialized countries for whom hepatitis B vaccine has been recommended, health care workers make up the great majority of vaccinees (Alter et al., 1988). As a consequence, most anaphylactic reactions have been observed in adult health care workers, of whom over 2 million have now been vaccinated against hepatitis B virus. Most of the documented cases of anaphylaxis occurred in women. This does not, however, justify a conclusion that women are more susceptible than men to anaphylaxis caused by hepatitis B vaccine, because women represent the majority of health care professionals for whom hepatitis B vaccine has been recommended.
Evidence for Association
The possibility of a causal relation between hepatitis B vaccination and anaphylaxis is supported by biologic plausibility, by the temporal sequence of observed events following vaccination, and by the observation of a spectrum of host responses to the hepatitis B vaccine that follow a logical biologic gradient from true anaphylaxis to milder hypersensitivity reactions. Biologic plausibility derives from the knowledge that injection of foreign protein into humans can be expected to elicit, in some percentage of recipients, immunoglobulin E (IgE)-mediated responses that present as anaphylaxis.
No specific inciting antigen has been demonstrated, and it is not known