Dr. Anthony Fauci, director of the National Institute of Allergy and Infectious Diseases, said that changes in vaccine distribution could be necessary depending on what happens in the next few weeks.

Anthony Fauci, director of the National Institute of Allergy and Infectious Diseases, speaks with Health and Human Services Secretary Alex Azar (unseen) before receiving his first dose of the Covid-19 vaccine at the National Institutes of Health on December 22, 2020, in Bethesda, Maryland. (Photo by Patrick Semansky / POOL / AFP) (Photo by PATRICK SEMANSKY/POOL/AFP via Getty Images)