Adverse reactions reported following receipt of Haemophilus influenzae type b vaccine: an analysis after 1 year of marketing.

An analysis of adverse reactions occurring after receipt of Haemophilus influenzae type b vaccine and reported to the Food and Drug Administration during the first year of marketing of the product was performed. During the period April 1985 to May 1986, adverse reaction reports on 152 patients, excluding those of vaccine failure and concurrent infection, were received. Several adverse reactions not previously recognized, including convulsions, allergic reactions such as anaphylactoid-like and serum sickness-like reactions, and vomiting were received. The vast majority of adverse reactions were benign. Because there are many biases that result in the reporting of or failure to report an adverse reaction, it is not possible to derive a rate of reactions from these data. Furthermore, causality cannot be inferred from any single report. The data, however, indicate that, in light of widespread use of the vaccine, its use appears to be safe.