Biden also participated in a moment of silence, standing by 500 lighted candles outside the White House, joined by first lady Jill Biden, Vice President Kamala Harris and second gentleman Doug Emhoff.

A flag atop the White House and flags at the US Capitol were lowered to half-staff Monday afternoon.

The pandemic is far from over as more than 1,200 American deaths were reported Monday.

But Americans can steer its course — and help prevent many more families from suffering inconsolable grief.

Major challenges ahead

“If that takes over, the numbers are going to start to spiral up again. There’s no end to what the death toll will look like unless we can vaccinate ahead of it.”

Where we stand with vaccinations

But the US will likely be caught up by the middle of this week, said Dr. Anthony Fauci, director of the National Institute of Allergy and Infectious Diseases.

“Obviously it is a setback because you’d like to see the steady flow of vaccine getting out there to get into people’s arms, but we can play pretty good catch-up,” Fauci told NBC on Sunday.

Both vaccines on the US market — developed by Pfizer-BioNTech and Moderna — require two doses, the second of which are intended to be administered 21 days and 28 days after the first, respectively.

Fauci told CNN Sunday the US is currently sticking with the vaccine schedule that is backed up by data from clinical trials.

“The science points directly towards continuing with what we know … 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.

Daily deaths have declined 24% this past week compared to the previous week, according to data from Johns Hopkins University.

Dr. Rochelle Walensky, director of the CDC, earlier Monday touted encouraging numbers in declining new cases, deaths, and hospital admissions, but also offered a note of caution.

The seven-day average of deaths reported each day is at its the lowest since the beginning of December, she said.

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. While the pandemic is heading in the right direction there is still much work to do.”

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

‘Now is not the time to let your guard down’

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.

There may be other ways everyday life will be different from the past, said infectious disease specialist and epidemiologist Dr. Celine Gounder.

“I do think we’re looking at some new normals. I think the handshake, for example, is probably going away,” she said.

“I do think masks in the cough/cold/flu season in the winter months would make a lot of sense. That clearly, really insulated the Southeast Asian countries from some of the worst of this, understanding the importance of wearing masks.”

“It’s estimated that about 70% of Americans must be vaccinated before we get to herd immunity through vaccination,” CNN medical analyst Dr. Leana Wen said. “That’s the point where enough people have the immune protection that the virus won’t spread anymore.”

And slowing the transmission of coronavirus also hinders the chances of the virus mutating further.

“The evidence was pretty compelling by last March or April that uniform wearing of masks would reduce transmission of this disease,” National Institutes of Health Director Dr. Francis Collins told “Axios on HBO” on Sunday.

The politicization of face masks probably led to many unnecessary deaths, he said.

“A mask is nothing more than a life-saving medical device, and yet it got categorized in all sorts of other ways that were not factual, not scientific and, frankly, dangerous,” he added. “And I think you can make a case that tens of thousands of people died as a result.”