The European Medicines Agency on Wednesday launched a rolling review of a variant-adapted Covid-19 vaccine developed by Pfizer and BioNTech, as cases of new sub-variants of the coronavirus's Omicron lineage rise.
When available, clinical trial data will be added to the rolling submission, which is designed to speed up any approval, BioNTech and Pfizer said in a joint statement.
The pair added they would also begin submitting data on the planned variant-adapted vaccine to the U.S. Food and Drug Administration over the next few weeks.
"The rolling review will continue until there is enough data for a formal application," the EU regulator said in a separate statement.
The companies said they were still working on several variant-adapted vaccines and the final composition was subject to discussions with global regulators.
While a new Omicron-driven wave of infections has been widely expected in the northern hemisphere fall or winter, a European disease monitoring agency this week warned cases could surge soon, citing the spread of particularly contagious sub-variants.
Rival Moderna, which is also pursuing a new shot against a jump in infections in the fall season, said last week a new version of its vaccine produced a better immune response against Omicron than the original shot.
Moderna plans to submit data on the vaccine, which it describes as bivalent because it targets Omicron as well as the original coronavirus strain, to regulators in the coming weeks.
BioNTech and Pfizer had originally favored a vaccine that targets Omicron only but widened their development efforts after EMA urged them to also consider bivalent versions.