The request to the Food and Drug Administration was for a so-called bivalent vaccine containing the dominant BA.4/BA.5 variants of the virus along with the original coronavirus strain. It is intended for ages 12 and above.
Pfizer said it was ready to deliver doses for September under a $3.2 billion deal in place with the U.S. government for 105 million doses, including the Omicron-tailored shots.
"Having rapidly scaled up production, we are positioned to immediately begin distribution of the bivalent Omicron BA.4/BA.5 boosters, if authorized," Pfizer Chief Executive Albert Bourla said in a statement.
Countries including the UK, the United States and EU members have been preparing for vaccination campaigns in the fall to protect against future surges. Britain became the first country to clear a bivalent vaccine, made by Moderna, last week.
The FDA in June asked COVID-19 vaccine makers to tailor shots to target the two subvariants, and said it would not require new studies testing the shots in humans for authorization, similar to how annual changes to flu vaccines are handled.
A mid-to-late-stage study of Pfizer's older BA.1-tailored vaccine has shown that the new shot generated a superior immune response against the subvariant compared with the original one.
A study of the BA.4/BA.5 vaccine in people aged 12 years and older is expected to start this month.
(Reporting by Manas Mishra in Bengaluru; Editing by Devika Syamnath)
