At a Senate subcommittee hearing on Wednesday, Redfield said a vaccine won't be widely available to the American public until the summer or early fall of 2021.

"There will be vaccine that will initially be available sometime between November and December, but very limited supply and will have to be prioritized," Redfield said Wednesday.

Anthony Fauci, director of the National Institute of Allergy and Infectious Diseases, has said experts probably won't know whether a vaccine is safe and effective until the end of 2020.

During a Wednesday press call, Mango said the US was on track to "vaccinate every American before the end of first quarter 2021." He added that the Food and Drug Administration would likely grant emergency authorization for a coronavirus vaccine by the end of 2020. .

Regardless of when the first doses of a vaccine become available, public-health experts will likely continue to recommend face masks for the American public well into next year

That's because the FDA has said it will authorize a vaccine if it's at least 50% more effective than a placebo at preventing or reducing the severity of the disease — so it wouldn't eliminate your risk of getting a coronavirus infection