Booster shots appear to be at least 90% effective against hospitalization for Delta and Omicron. But Omicron poses a greater challenge to vaccine protection, according to three new CDC studies.

Neutralizing antibody levels rose 37-fold one month after the booster was given. Moderna announced Monday that its COVID-19 vaccine booster increases antibody levels against the omicron variant within ...

Protection is high against severe disease, and is boosted by a third shot, per official UK stats. Protection against getting mildly ill is much lower, although a booster raises it. A new chart hows ...