While mRNA vaccines from Moderna (NSDQ:MRNA) and Pfizer (NYSE:PFE) had 95% efficacy in Phase 3 clinical trials, their effectiveness in the real world has dropped with the rise of the Delta variant.
As a result, breakthrough infections have grown more common in people who have received two doses of mRNA vaccines.
Ultimately, full vaccination may require three doses, concluded Chief Medical Advisor to the President Dr. Anthony Fauci in a press briefing. While acknowledging that the FDA would need to make the final decision, “I must say from my own experience as an immunologist, I would not at all be surprised that the adequate full regimen for vaccination will likely be three doses,” Fauci said.
In the briefing, Fauci pointed to booster data emerging from Israel recently published in a preprint. The Pfizer-BioNTech vaccine led to a 70% to 84% risk reduction 14 days after admin…