Chapter 8 - How Vaccine Safety is Monitored

Abstract

Safety expectations for vaccines are high because they are administered to healthy and sometimes vulnerable populations. Also, vaccines are endorsed and required by most governments. Although no biologic or medical intervention is perfectly safe, vaccines are generally very safe and the risks of side effects are almost always greatly outweighed by the benefits derived from vaccination to prevent disease. Vaccine safety is evaluated at all stages of development, including preclinical animal and laboratory studies, phase 1–3 clinical trials, and after licensure. Regulatory authorities conduct in-depth reviews of investigational new vaccines prior to approval for licensure and usually require postlicensure surveillance and special studies. Many industrialized countries conduct clinical assessment of postlicensure adverse events and individual-level causality assessment. National authorities in many countries compensate persons who may have been injured by vaccines. Vaccine safety programs are coordinated in many countries and internationally. Questions about vaccine safety will undoubtedly continue to occur, and continuous monitoring will be needed to address these questions with rigorous scientific methods to help assure the public that vaccines are made as safe as possible.