Overall, they suggest that boosters helped protect against both infection and symptomatic disease. Adults aged 50 and older saw the most benefit from an extra dose of the vaccines made by BioNTech SE with Pfizer Inc or Moderna Inc.
Boosters provide 'added protection' against Omicron -CDC
The studies, led by the CDC, are among the first in the United States to look at the impact of booster doses against the fast-spreading Omicron variant, which now accounts for 99% of all new COVID cases.