Pfizer says booster shots are needed to better protect against Omicron variant

Pfizer and BioNTech say a third dose of their COVID-19 vaccine is needed to fully protect against the Omicron variant. Recent studies show two doses of the shot are "significantly less effective at blocking the virus." John Moore, professor of microbiology and immunology at Weill Cornell Medical College, joins CBSN's Tanya Rivero to discuss the new variant and the latest vaccine information.