The Biden administration is preparing for the possibility that people will need a third dose of the Pfizer COVID-19 vaccine within a year of receiving their initial jab.
Pfizer Inc Chief Executive Albert Bourla said people will “likely” need a third booster dose of COVID-19 vaccines within 12 months and could need annual shots, in comments made on 1 April and reported by CNBC overnight.
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.
"The current thinking is those who are more vulnerable will have to go first," he said.
Initial data has shown that vaccines from Moderna Inc and partners Pfizer Inc and BioNTech SE retain most of their effectiveness for at least six months, though for how much longer has not been determined.
Even if that protection lasts far longer than six months, experts have said that rapidly spreading variants of the coronavirus and others that may emerge could lead to the need for regular booster shots similar to annual flu shots.
The United States is also tracking infections in people who have been fully vaccinated, Rochelle Walensky, director of the US Centres of Disease Control and Prevention told the House subcommittee hearing.
Of 77 million people vaccinated in the United States, there have been 5,800 such breakthrough infections, Walensky said, including 396 people who required hospitalisation and 74 who died.
Ms Walensky said some of these infections have occurred because the vaccinated person did not mount a strong immune response. But the concern is that in some cases, they are occurring in people infected by more contagious virus variants.
Earlier this month, Pfizer and partner BioNTech said their vaccine was around 91 per cent effective in preventing COVID-19, citing updated trial data that included more than 12,000 people fully inoculated for at least six months.
