February 25, 2021 – Pfizer Inc. and BioNTech SE announced they have begun an evaluation of the safety and immunogenicity of a third dose of the Pfizer-BioNTech COVID-19 vaccine (BNT162b2) to understand the effect of a booster on immunity against COVID-19 caused by the circulating and potential newly emerging SARS-CoV-2 variants.
The study will draw upon participants from the Phase 1 study in the U.S. who will be offered the opportunity to receive a 30 µg booster of the current vaccine 6 to 12 months after receiving their initial two-dose regimen.
The study is part of the companies’ clinical development strategy to determine the effectiveness of a third dose against evolving variants.
Separately, in order to be prepared for any potential future strain changes, Pfizer and BioNTech are in ongoing discussions with regulatory authorities, including the U.S. Food and Drug Administration (FDA) and the European Medicines Agency, regarding a registration-enabling clinical study to evaluate a variant-specific vaccine having a modified mRNA sequence.
This could position the companies to update the current vaccine quickly if the need arises to protect against COVID-19 from circulating strains.
More important, perhaps, is that in alignment with the updated guidance issued by the FDA regarding emergency use of vaccines to prevent COVID-19 which provides recommendations for evaluating a modified vaccine to address variants, the companies are hoping to pursue the validation of future modified mRNA vaccines with a regulatory pathway similar to what is currently in place for flu vaccines.