Science writer explains why it's unlikely U.S. will reach "herd immunity"
Despite a decline in new COVID-19 cases and increasing vaccinations, some experts say it's unlikely America will reach "herd immunity." Science writer Carl Zimmer, author of The New York Times "Matter" column, joins CBSN's "Red & Blue" host Elaine Quijano to explain why. He also discusses the next generation of coronavirus vaccines and what is currently known about a variant prevalent in India that's been detected in the U.S.