HealthDay News – A review of all safety-related labeling changes for FDA-approved vaccines during a 20-year period shows vaccines are largely safe, and many of the safety issues are identified through postmarketing surveillance, according to a study published online July 28 in the Annals of Internal Medicine.
Noam Tau, MD, from Tel Aviv University in Israel, and colleagues conducted a retrospective cohort study to describe the prevalence and characteristics of postapproval, safety-related label changes on initial and subsequent labels of 57 US Food and Drug Administration-approved vaccines between January 1, 1996, and December 31, 2015.
The researchers found that for 93% of the vaccines, initial approval of the vaccines was supported by randomized controlled trials, with a median cohort size of 4161 participants. Fifty-eight postapproval, safety-related label modifications were identified in association with 25 vaccines (49 warnings and precautions, 8 contraindications, and 1 safety-related withdrawal). Vaccines with and without postmarketing, safety-related label modifications had similar initial approval trial characteristics. Expansion of population restrictions was the most common safety issue triggering label modifications, followed by allergies (36 and 22%, respectively). Postmarketing surveillance was the most common source of safety data (48%).
“A large proportion of emerging safety issues were rapidly identified through current postmarketing surveillance programs, including the safety signal, which led to the withdrawal of a single vaccine,” the authors write.