EMAEuropean Medicines Agency (EMA) has begun a rolling review for updated versions of Moderna’s and Pfizer/BioNTech’s vaccines modified to optimize protection against newer variants of SARS-CoV-2.

Earlier this month, Moderna (Nasdaq:MRNA) announced that its Omicron-containing bivalent COVID-19 booster candidate, mRNA-1273.21, provided an antibody response that was statistically superior to the original version of the vaccine, mRNA-1273.

EMA has also begun a rolling review of an updated version of the COVID-19 vaccine from Pfizer Inc. (NYSE:PFE) and its partner BioNTech SE (Nasdaq:BNTX).

EMA’s review will first focus on data from laboratory studies in addition to chemistry, manufacturing and controls (CMC) data associated with the manufacture of the vaccines.

The vaccine developers will ultimately provide EMA with more information as part of the rolling review process.

While mRNA-1273.21 is Moderna’s lead candidate for the fall and winter season, a number of public health authorities, including the WHO, EMA and other members of the International Coalition of Medicines Regulatory Authorities (ICMRA), will offer feedback to determine which SARS-CoV-2 variants are most important for modified COVID-19 to target.

In a press release, Pfizer and BioNTech note that they are testing several variant-adapted vaccines.