| − | '''Adverse events''' are undesirable experiences occurring after [[immunization]] that may or may not be related to the [[vaccine]].<ref>http://www.cdc.gov/vaccines/about/terms/glossary.htm#a</ref> | + | '''Adverse events''' are undesirable experiences occurring after [[immunization]] that may or may not be related to the [[vaccine]].<ref>https://www.cdc.gov/vaccines/about/terms/glossary.htm#a</ref> |