WASHINGTON - President Donald Trump on Thursday said that a vaccine may be produced ahead of the US presidential election on November 3 -- a more optimistic timeline than given by his top infectious diseases doctor.

Asked by radio talk show host Geraldo Rivera whether a vaccine could come by the election, Trump said: "I think in some cases, yes, possible before. But right around that time."

Trump said the vaccine would be ready "sooner than the end of the year. Could be much sooner."

"We have a lot of vaccines under study by the way. We look like we're going to be really good on vaccines and therapeutics also," he said.

A more careful note was sounded on Wednesday by Dr. Anthony Fauci, a lead government official on the fight against the coronavirus pandemic.

Fauci said he was "cautiously optimistic" of success and that "somewhere towards the end of the year, the beginning of 2021, we will know whether they have a safe and effective vaccine."

The Trump administration is pouring federal funds into vaccine development, seen as the only way to stop the virus and end the mass shutdowns and social distancing that have crippled economies around the world.