US preparing for 1-year Covid-19 booster shots; Pfizer chief sees need

The United States is preparing for the possibility that a booster shot will be needed between nine to 12 months after people are initially vaccinated against Covid-19, a White House official said on Thursday.

While the duration of immunity after vaccination is being studied, booster vaccines could be needed, David Kessler, chief science officer for President Joe Biden's Covid-19 response task force told a congressional committee meeting...