Like any vaccine, COVID-19 vaccines can cause mild, short-term side effects, such as a low-grade fever, or pain or redness at the injection site. Most reactions to vaccines are mild and go away within a few days on their own. More serious or long-lasting side effects to vaccines are possible but extremely rare. Vaccines are continually monitored by the Regulator for as long as they are in use, to detect rare adverse events and implement approaches to limit their occurrence. [1]