There's no end to what the death toll will look like unless we can vaccinate ahead of it."

But as the number of vaccinations slowly increase, some Americans say they won't get a Covid-19 vaccine -- hurting the chances of herd immunity and hindering a return to normal life.

from the clinical trial," he said.

Good news (for now) on cases and hospitalizations

Nationwide, the rates of new Covid-19 cases, hospitalizations and deaths are declining.

The number of patients hospitalized with Covid-19 has fallen for the 40th day in a row, according to the COVID Tracking Project.

At a White House coronavirus task force briefing held before the death toll was updated, Walensky noted the falling death rate but said the total number of Covid-19 fatalities is "a truly tragic reminder of the enormity of this pandemic, and the loss it has afflicted on our personal lives and our communities.

But that figure is probably nowhere near the actual number of variant cases in the US, since the US has lagged behind dozens of other countries in genome sequencing per 1,000 Covid-19 cases.

Walensky has said the US has ramped up sequencing to find variants and will keep doing so.

The vast majority of variant cases so far involve the highly contagious B.1.1.7 variant first detected in the UK.

"Managing the epidemic in the next four months depends critically on scaling up vaccination, trying to increase the fraction of adults willing to be vaccinated above three-quarters, and strongly encouraging continued mask use and avoiding situations where transmission is likely, such as indoor dining, going to bars, or indoor gatherings with individuals outside the household," the team wrote.

The American Medical Association, the American Hospital Association and the American Nurses Association also pleaded for Americans to help quash the pandemic.

"With new, more contagious variants of the virus circulating throughout the U.S., now is not the time to let your guard down and scale back on the measures that we know will work to prevent further illness and deaths -- wearing masks, practicing physical distancing, and washing hands," a joint statement said.

Why we could be wearing masks next winter, too

Some Americans have discovered an unexpected perk to wearing masks in the winter -- they protect against brutally cold air, not just against coronavirus.

And Americans might be wearing them next winter, when some health experts say Covid-19 might flare up again.

Fauci hopes that doesn't happen, he said, adding it's "possible" people may be wearing masks in 2022.

That clearly, really insulated the Southeast Asian countries from some of the worst of this, understanding the importance of wearing masks."

For those who have already been vaccinated, health experts say they should keep wearing a mask.