The CEO of Pfizer says the pharmaceutical company's COVID-19 vaccine recipients will "likely" need a third dose between six to 12 months after full vaccination, followed by an annual shot.
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. But the lasting effect of the vaccine is still being studied.
CEO Albert Bourla told US TV network CNBC that boosters were expected to become a regular part of life for years to come, as variants continue to spread.
"There will be a need for revaccinations. [The] likely scenario is that there will likely be need for a third dose. And then from there, there will be an annual revaccination. But all of that needs to be confirmed," Mr Bourla told the network.
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.
Earlier this month, Pfizer and partner BioNTech said their vaccine was about 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.
A White House official said the US government was preparing for the possibility that a booster shot would be needed between nine to 12 months after initial vaccination.
David Kessler, chief science officer for President Joe Biden's COVID-19 response taskforce, told a congressional committee meeting booster dosages would be administered according to vulnerability to coronavirus.
"The current thinking is those who are more vulnerable will have to go first," he said.
Meanwhile, the US is also tracking infections in people who have been fully vaccinated, Rochelle Walensky, director of the US Centers for Disease Control and Prevention told the House subcommittee hearing.
Of 77 million people vaccinated in the US, there have been 5,800 such breakthrough infections, Dr Walensky said, including 396 people who required hospitalisation and 74 who died.
Dr Walensky said some of these infections had 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.
Reuters/ABC
