Top FDA officials oppose Operation Warp Speed idea to halve vaccine doses for some Americans

Two top FDA officials are opposing the White House's idea of altering the size or number of agency-approved coronavirus vaccines, saying the move is "premature" because of insufficient data. 

Dr. Moncef Slaoui, the chief scientific adviser for Operation Warp Speed, the White House's COVID-19 vaccination effort, on Sunday suggested — based on early data — the idea of halving the Moderna vaccine for people 18 to 55, which would make the vaccine available to twice as many people in that age group. 

FDA Commissioner Dr. Stephen Hahn and Dr. Peter Marks, who leads the agency's vaccine division, said Monday that anyone getting either the Moderna or Pfizer vaccine must get two full doses and opposed cutting doses in half. 

"These are all reasonable questions to consider and evaluate in clinical trials," they said. "However, at this time, suggesting changes to the FDA-authorized dosing or schedules of these vaccines is premature and not rooted solidly in the available evidence. Without appropriate data supporting such changes in vaccine administration, we run a significant risk of placing public health at risk, undermining the historic vaccination efforts to protect the population from COVID-19."