The Possibility of COVID-19 after Vaccination: Breakthrough Infections Updated Dec. 17, 2021 Print COVID-19 vaccines are effective at preventing infection, serious illness, and death. Most people who get COVID-19 are unvaccinated. However, since vaccines are not 100% effective at preventing infection, some people who are fully vaccinated will still get COVID-19.
An infection of a fully vaccinated person is referred to as a “vaccine breakthrough infection.”