Are expired vaccines unsafe?
The expiry date of vaccines is based on the period for which there is evidence that they retain their potency, so vaccines that have passed their expiry date may not protect you against the virus. Expiry dates are not determined based on safety considerations.
Expired vaccines should not be used.
Sources
Coronavirus disease (COVID-19) vaccines Q&A
https://www.afro.who.int/health-topics/coronavirus-covid-19/vaccines/qa