COVID-19 vaccines work in two ways. They protect against COVID-19 infection but also severe sickness, hospitalization, and death. Although the vaccines don’t stop all infections and their effectiveness can decrease over time, vaccinated people are less likely to get very sick or die if they are infected. This explains how vaccines can still work even if some vaccinated people get infected.

Vaccines are effective in protecting against COVID-19. However, a fully vaccinated person can still get infected because most vaccines are not 100% effective. This is known as vaccine breakthrough infection.

If fully vaccinated (and boosted) people are infected with COVID-19, they are less likely to develop serious complications, be hospitalized, or die because vaccines work to protect from 1) getting infected and 2) becoming seriously ill if infected.

An unvaccinated person is at a higher risk of getting infected with COVID-19 and becoming very ill.

It is unclear if the current COVID-19 vaccines will protect against future variants or if more booster shots will be needed.