Principal Controversies in Vaccine Safety in the United States.

Concerns about vaccine safety can lead to decreased acceptance of vaccines and resurgence of vaccine-preventable diseases. We summarize the key evidence on some of the main current vaccine safety controversies in the United States, including (1) measles, mumps, and rubella vaccine and autism; (2) thimerosal, a mercury-based vaccine preservative and the risk of neurodevelopmental disorders; (3) vaccine-induced Guillain-Barré syndrome (GBS); (4) vaccine-induced autoimmune diseases; (5) safety of human papillomavirus vaccine; (6) aluminum adjuvant-induced autoimmune diseases and other disorders; and (7) too many vaccines given early in life predisposing children to health and developmental problems. A possible small increased risk of GBS following influenza vaccination has been identified, but the magnitude of the increase is less than the risk of GBS following influenza infection. Otherwise, the biological and epidemiologic evidence does not support any of the reviewed vaccine safety concerns.