- Pfizer says booster dose of vaccine protects against omicron variantNBC News
- Two vaccine doses may not provide sufficient protection against Omicron coronavirus variant, but protection improves with three doses, Pfizer saysCNN
- Pfizer Shot Provides Partial Omicron Shield in TestBloomberg
- Omicron Infections Now Identified In Over A Third Of The U.S.NBC News
- Pfizer Says Two Doses Might Not Fight Omicron but Three WillThe Daily Beast