The CDC recently expanded eligibility for COVID-19 booster shots to all adults.
- Studies show after getting vaccinated against COVID-19, protection against the virus and the ability to prevent infection with the Delta variant may decrease over time.
- This lower effectiveness is likely due to the combination of decreasing protection as time passes since getting vaccinated, as well as the greater infectiousness of the Delta variant.
- Data from small clinical trials show that vaccine effectiveness against COVID-19 infection is waning after the primary series, but protection remains high against severe disease and hospitalization.
