The comments come as President Donald Trump asserts on the campaign trail that the United States is "rounding the turn" on the virus.
"Now, as we're getting into the cold weather, we came back up again to the worst that we've ever had, which was over 80,000 per day", he said, adding that he views the surge as "an elongated and an exacerbation of the original first wave".
But Fauci said on CNBC that "we are on a very hard trajectory", and if things don't change, "there's going to be a whole lot of pain in this country with regard to additional cases and hospitalizations and deaths".
He said: 'If we get a vaccination campaign, and by the second or third quarter of 2021 we have vaccinated a substantial proportion of the people, I think it will be easily by the end of 2021, and perhaps even into the next year, before we start having some semblances of normality'.
It's not likely that life will return to "some semblances of normalcy" before the end of next year, or even until 2022, even though a vaccine is near, according to Dr. Anthony Fauci.
"We have 225,000 deaths, the modeling tells us we're going to get one hundred or more thousand as we get into the winter, that is just something that's unacceptable", The Hill news website quoted the top expert as saying.
The school said Fauci spoke for about 20 minutes, on the public health and scientific challenges of the COVID-19 pandemic and what is next - which he hopes is a vaccine candidate in the very near future.
Fauci appeared hopeful about the ongoing vaccine trials, but encouraged Americans not to rely on the prospect of a vaccine and instead continue to social distance and wear masks. And the Trump administration is reportedly pushing the controversial herd immunity strategy, which health officials warn could result in skyrocketing infections and deaths.
For his part, Fauci described a very different reality during a CNBC interview on Wednesday.
"I know that was carried in the news globally", he said.
As of Thursday morning, there are more than 8.8 million confirmed cases of coronavirus since the pandemic started in the US, and more than 227,000 deaths. "We are going in the wrong direction".
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