Are vaccines safe for my child?
Before a new vaccine is ever given to people, extensive lab testing is done. Once testing in people begins, it can still take years before clinical studies are complete and the vaccine is licensed.
After a vaccine is licensed, the Food and Drug Administration (FDA), Centers for Disease Control (CDC), National Institutes of Health (NIH), and other federal agencies continue routine monitoring and investigate any potential safety concerns.
Vaccines are very safe. Most vaccine adverse events are minor and temporary, such as a sore arm or mild fever. More serious adverse events occur rarely (on the order of one per thousands, to one per millions of doses).
Source: National Center for Immunization and Respiratory Diseases (2023, July 19). Vaccines are safe.