- Why three? Earlier this month, manufacturers Pfizer/BioNTech said they would ask US and European authorities for permission to provide a third dose of their vaccine.
They said this was aimed at ensuring stronger immunity in individuals than that bestowed by two doses. The developers said that two doses of their vaccine protected against severe Covid-19 for at least six months.
But faced with emerging variants, they said they anticipated some decline in efficacy over time. The White House's chief medical advisor Anthony Fauci, speaking on CNBC on Tuesday, said Pfizer/BioNTech's third-dose application was "an appropriate preparation (for) the eventuality that you might need a booster". "But when you translate that into, 'We will need