Children's Vaccines Health Center

Side effects from vaccines

Some people question the safety of immunizations for children. Although minor discomfort sometimes follows vaccine injections, research does not support claims that immunizations put a child at any significant risk for harmful side effects. The U.S. Food and Drug Administration (FDA) carefully evaluates all vaccines for safety. Federal law requires health professionals to report any reaction following an immunization to the Vaccine Adverse Events Reporting System (VAERS). Only two vaccines-the 1976 swine influenza vaccine and the old rotavirus vaccine in 1999-have ever been recalled because of safety concerns.

Side effects from vaccines are generally minor, if they occur at all. The area where the shot was given may be sore. And some children may be fussy or get a slight fever. More serious side effects are very rare. The risk of a serious complication from a disease is far greater than the risk from the vaccine.

The U.S. Centers for Disease Control and Prevention (CDC) vaccine information statements list the side effects of each vaccine. For more information, see the topic Vaccine Information Statements.

The CDC and the FDA continue to study vaccines. Although the risk of problems from vaccines is already extremely low, these agencies watch for any reports of rare or unexpected reactions.

Exposure to mercury

In the past, thimerosal, a mercury-containing compound, was added to vaccines to prevent bacterial growth. In 1999, the U.S. Advisory Committee on Immunization Practices (ACIP) responded to concern about this additive's safety and set a goal to have it removed from all childhood vaccines made in the U.S. Even though studies do not show a link between thimerosal and autism or any other condition, all routinely recommended U.S. childhood vaccines contain either no thimerosal or only trace amounts.¹

The FDA keeps a list of all vaccines that are given to children and how much, if any, thimerosal the vaccines contain. To view the list, go to www.fda.gov/BiologicsBloodVaccines/SafetyAvailability/VaccineSafety/UCM096228.