Are vaccines safe?

Yes. They undergo extensive trials and ongoing post-marketing surveillance. Common reactions are sore arm, mild fever, and fatigue; serious adverse events are rare and far outweighed by the diseases prevented. The claimed autism link was based on fraudulent, retracted research.

Vaccine safety is monitored after approval through national reporting systems, which is how rare effects are detected across millions of doses.

Comparison helps: the risk of serious complication from measles, tetanus or influenza is orders of magnitude higher than from the corresponding vaccine.