There is no scientific data to support giving just a single dose of the Pfizer/BioNTech or Moderna Covid-19 vaccines, Dr. Anthony Fauci said on Tuesday.
The vaccines were authorized to be given as two doses and the US Food and Drug Administration on Monday nixed any idea of changing that regimen to stretch supply.
"There really is no scientific basis in a clinical trial that proves that giving a dose to more people and maybe waiting instead of the 21 or 28 days that the science told us is the correct interval to going out three, maybe four months to the second dose," Fauci, director of the National Institute of Allergy and Infectious Diseases, told Newsday's Randi Marshall during a virtual event.
"That is something that is taking a chance and we prefer to make all of our decisions based on the scientific data that we have," Fauci said. "There is not scientific data to back that up. It might work. ... But we don't have good scientific data to prove that."