US President Donald Trump said on Friday he expects a coronavirus vaccine to be available for the entire population as soon as April, amid a crush of new infections of the deadly disease that has pushed daily case counts to record highs.

In his first public remarks in over a week following his election loss to Democratic challenger Joe Biden, Trump also said he expects an emergency use authorisation for Pfizer's vaccine "extremely soon."

Pfizer has said it expects to report required safety data next week and can then apply for an emergency use authorisation.

The remarks came after Trump received an update on 'Operation Warp Speed,' an administration effort to turbocharge development of a vaccine.

Criticism of the administration's response to the virus, which has killed more than 235,000 Americans, became a rallying cry for Democrats ahead of November 3 elections.

US networks have proclaimed Biden the winner of the presidential vote, but Trump, refusing to concede, has launched a series of legal challenges based on unsubstantiated claims of fraud.

On Friday, Trump appeared to acknowledge the possibility of an upcoming Biden administration.

"Ideally, we won't go to a lockdown. I will not go, this administration will not be going to a lockdown," he said in a Rose Garden address. "Hopefully the, the – uh – whatever happens in the future – who knows which administration will be. I guess time will tell," he added.