Pfizer CEO Albert Bourla. (Photo: Reuters)

Bourla said Pfizer will produce an additional billion doses, bringing the total to three billion, adding that donations to other countries with lower vaccination rates will not affect efforts to administer booster shots in the US.

Five hundred million vaccine doses of the two billion that Pfizer has produced have already been delivered to countries with low vaccination rates, according to Bourla.

The statement came after the World Health Organization called on developed countries to halt booster shots until 2022 and donate their surplus vaccine doses to poorer countries.