The United States began its rollout of the Omicron-tailored shots from Pfizer/BioNTech and Moderna earlier this month.
A federal health agency said on Tuesday that over 25 million doses of the so-called bivalent shots had been sent out. That consisted of mostly the Pfizer/BioNTech vaccine, as production of the Moderna vaccine ramps up.
The redesigned boosters aim to tackle the BA.5 and BA.4 Omicron subvariants, which make up 84.8% and 1.8%, respectively, of all circulating variants in the United States, based on latest data.
(Reporting by Manas Mishra in Bengaluru; editing by Uttaresh.V)