Dr. Barney Graham, left, speaks as President Joe Biden listens during a visit to the Viral Pathogenesis Laboratory at the National Institutes of Health (NIH), Thursday, Feb. 11, 2021, in Bethesda, Md. Kizzmekia Corbett, an immunologist with the Vaccine Research Center at the NIH, right, and NIH Director, second from right, listen. (AP Photo/Evan Vucci)