'A natural disaster ... in all 50 states' is unfolding just as travelers disperse nationwide after Thanksgiving

"And then it takes usually another week for folks to succumb to the illness."

So infections picked up on Thanksgiving "are going to show up in three weeks and are going to show up in deaths over Christmas and New Year's and are going to spread in every state," Ranney said.

At least 1,189 new deaths were reported on Saturday alone, according to Johns Hopkins University.

More than 266,000 people in the US have died from Covid-19 since the pandemic began.

Birx: 'If you're young and you gathered,' get tested

Health experts say anyone who gathered with people outside their household should take serious precautions in the coming days, especially young people who might be carrying and spreading coronavirus without any symptoms.

"If you're young and you gathered, you need to be tested about five to 10 days later," said Dr.

"You need to assume that you're infected and not go near your grandparents and aunts and others without a mask."

Birx, a member of the White House coronavirus task force, recommended those over age 65 get tested immediately if they develop any symptoms.

"If you're over 65 or you have comorbidities and you gathered at Thanksgiving -- if you develop any symptoms, you need to be tested immediately," she said.

ER doctor wants people to follow stay-at-home orders

Many hospitals are on the brink of exceeding capacity, threatening reduced care for everyone -- even those without coronavirus.

In Los Angeles County, a three-week stay-at-home order goes into effect on Monday.

"What I wish is that people would follow those stay-at-home orders," said Ranney, the emergency medicine physician in Rhode Island.

"I can't tell you how many patients I take care of who tell me, 'Well, I just went to an indoor restaurant.' Or, 'I just went to a party with a few friends.

I didn't actually think I was going to catch Covid.' So those stay-at-home orders are critical."

The Los Angeles County stay-at-home order prohibits all public and private gatherings with people outside a single household.

"Residents are advised to stay home as much as possible and always wear a face covering over their nose and mouth when they are outside their household and around others," the county's public health department said.

The order is in effect through December 20.

It does not apply to "faith based services and protests, which are constitutionally protected rights," the health department said.

Essential retail businesses will be limited to 35% occupancy, while the occupancy limit for nonessential retail operations, personal care services and libraries will be 20%, the county said.

"Even if you're not feeling sick, the simple act of gathering with people outside your household puts everyone at risk," county health director Barbara Ferrer said.

Ranney said it's possible some schools and workplaces can operate safely if precautions are met.