Dr. Anthony Fauci, director of the National Institute of Allergy and Infectious Diseases, said on Friday that the second dose of the Moderna or Pfizer Covid-19 vaccine is essential for optimal protection.
“The second dose is absolutely critical,” Fauci said.
His comments came on the same day that CNN reported that the Biden administration will aim to release every available dose of the vaccine once he takes office. While quickly doing this could increase the number of people who receive their first dose of the vaccine, it may delay second doses for some. Under current guidance, the two doses of Pfizer’s vaccine must be administered 21 days apart, while Moderna’s two doses should be given 28 day apart.
Fauci said that one dose of Moderna or one dose of Pfizer “has not been proven to be efficacious to the degree that we want, and we don’t know how long the protection lasts.”
“Whatever you’re hearing, one dose of the Moderna and one dose of the Pfizer is not optimal,” Fauci said. “Optimal is one dose of Pfizer, followed in 21 days by the boost. Or one dose of Moderna followed in 28 days with a boost if you want optimal protection and optimal durability.”