Vaccines, the battle for the third dose. Europe and the USA: “Now we don’t need”

Pfizer will seek authorization to administer a third dose of its Covid vaccine, both in Europe and in the US. Today regulatory approval provides for two doses, but protection against infection is expected to decline over time. The need for a periodic booster has always been taken into consideration, but at the moment – 8-9 months after the first administration – there are no signs of a weakening of efficacy.