Departing FDA regulators pan Covid boosters in paper

Two senior U.S. vaccine regulators who are leaving the FDA came out against giving Covid-19 booster shots to the general population now in a research paper published Monday that concludes current science on vaccine efficacy doesn't support giving third shots to most Americans.

The paper, co-authored by Marion Gruber and Philip Krause and published in The Lancet, deals a blow to the FDA and to the Biden administration just days before an external agency panel is set to review the case for doling out Pfizer-BioNTech boosters. The scientists recently announced plans to retire this fall, decisions one former agency official said stemmed in part from frustration with the administration's booster plan.

The main argument: The paper, which summarizes available trial data and peer-reviewed studies to date on the Covid vaccines, argues that despite waning immunity, the shots' efficacy "is substantially greater against severe disease than against any infection" and sufficiently protective for the general population.

"Even in populations with fairly high vaccination rates the unvaccinated are still the major drivers of transmission and are themselves at the highest risk of serious disease," wrote the authors, which also include World Health Organization scientists.

Even if booster shots were shown to lower the risk of serious disease, they said, existing supplies would be better off deployed to unvaccinated corners of the world, rather than boosting vaccinated populations, to head off the development of more variants.