The push to boost every person in the United States has a scientific problem. New data show that vaccine booster efficacy against getting COVID can plummet to 35% with the Pfizer booster and 45% with the Moderna booster just 10 weeks after that third shot.
So will public-health officials recommend boosters every three months in perpetuity?
The public has no appetite for that. Nor do many experts. Antibodies represent one line of defense against early infection, but cellular immunity with B and T cells confers strong protection against severe disease. That’s why tracking antibody levels is a medically imprecise way to study immunity — and why public-health officials must make decisions driven by data.
To be clear, a single booster dose reduces the risk of hospitalization in older people. But with many vaccines in medicine, robust memory B and T cell immunity is sufficiently achieved after two or three doses, spaced apart properly.
Yet Moderna’s CEO has already suggested annual boosters, with no supporting clinical data. While his shareholders love that news, many experts do not. Dr. Vinay Prasad of the University of California this week nicely summarized the problem with using efficacy as the ultimate metric to evaluate a vaccine. In a recent Kaiser Southern California study, the efficacy of two doses of the mRNA vaccines went to essentially zero at 6 months, despite a lot of data showing that these same vaccines provide strong protection against hospitalization in younger people.