Pfizer and its partner BioNTech said Thursday they have begun to test how well a third dose of their authorized vaccine stacks up against new coronavirus variants.
The study will look at the safety and immune response of a booster dose in up to 144 participants from the earlier Phase 1 trial in the US, including a subset of older adults up to age 85. It will also involve testing how well their antibodies are able to neutralize “strains of interest” in the lab, the companies said.
Volunteers would receive a third dose between 6 and 12 months after their earlier two doses. The dosage would be identical to what’s currently authorized, 30 micrograms.
“This booster study is critical to understanding the safety of a third dose and efficacy against circulating strains,” Pfizer CEO Albert Bourla said in a statement.
Separately, Pfizer and BioNTech are also “in ongoing discussions with regulatory authorities” about potentially testing a vaccine has been modified to protect against concerning variants in a Phase 1/2 study.
However, Bourla noted the companies haven’t yet seen compelling evidence that variants are resistant to its vaccine, though they are taking steps to be prepared.
On Monday, the US Food and Drug Administration announced new guidelines that would streamline and quicken the process of updating vaccines to target variants. An agency official estimated this could involve a several hundred individuals and take a few months.