Gen. Gustave Perna tells NPR that if a safe and effective COVID-19 vaccine is approved by the Food and Drug Administration in December, “10 to 30 million doses of vaccine will be available that we can start distributing” in the United States.

Gen. Gustave Perna testifies before the Senate Armed Services Committee during a nominations hearing on Capitol Hill, Thursday, June 18, 2020, in Washington. (Chip Somodevilla/Pool via AP)