Pfizer-BioNTech Studying a COVID-19 Vaccine Booster

By Kelly Young

Edited by André Sofair, MD, MPH, and William E. Chavey, MD, MS

Pfizer and BioNTech said on Thursday that they will begin studying whether a third dose of their authorized mRNA vaccine is safe and effective against currently circulating and emerging strains of SARS-CoV-2.

Participants in the original phase I trial will be offered a 30-µg booster dose 6–12 months after their first doses.

The companies are also working with regulatory agencies to be able to tweak the mRNA sequence used in the vaccine to better protect against the B.1.351 lineage, which was discovered in South Africa. Their goal is to be able to quickly adapt to other potential variants, much like influenza vaccines can change every year.