Coronavirus updates: NYC deputies to enforce quarantine; COVID-19 antibodies likely protect from reinfection, studies show; 325K US deaths

USA TODAY is keeping track of the news surrounding COVID-19 as a pair of vaccines join the U.S. fight against a virus that has killed more than 325,000 Americans since the first reported fatality in February. Keep refreshing this page for the latest updates on vaccine distribution, including who is getting the shots and where, as well as other COVID-19 news from across the USA TODAY Network. Sign up for our Coronavirus Watch newsletter for updates directly to your inbox, join our Facebook group or scroll through our in-depth answers to reader questions for everything you need to know about the coronavirus.

In the headlines: 

►Pfizer and BioNTech announced an agreement with the U.S. government to supply an additional 100 million doses of the companies’ vaccine. This agreement brings the total number of doses to be delivered to the U.S. by July 31 to 200 million. Here's what experts have to say about vaccine distribution. 

►The AFC East champion Buffalo Bills are exploring a plan that would allow up to 6,700 fans to attend their remaining home games, including at least one in the playoffs. The plan, yet to be approved, calls for the use of rapid COVID-19 tests and contact tracing.

►Luke Letlow, a Louisiana Republican who was elected as a U.S. Representative in November, was transferred to the intensive care unit of a Shreveport hospital to continue treatment for COVID-19. Letlow, 40, is in stable condition.

►Canada authorized Moderna's vaccine and said shipments should enter the country within 48 hours. Health officials approved the Pfizer-BioNTech vaccine Dec. 9. Canada should get 40 million doses of Moderna’s vaccine in 2021, enough to vaccinate 20 million people, or about two-thirds of the country's adult population.

►The number of Americans seeking unemployment benefits dipped by 89,000 last week to a still-elevated 803,000, evidence that the job market remains under stress. Before the virus struck, jobless claims typically numbered around 225,000 a week.

►House Democrats said they plan to offer legislation increasing the $600 stimulus checks to $2,000 as proposed by President Donald Trump. The president's own party, however, was balking, and the fate of the increase remained in doubt Wednesday. 

►Another 3,401 U.S. deaths were recorded Wednesday, the second highest total on record, according to Johns Hopkins University data. It's the fifth time the death toll has surpassed 3,000 in one day, and all five times were this month. The U.S. for the first time reported more than 19,000 dead of COVID-19 in a seven-day period.

►Germany, with about one-quarter the population of the U.S., reported a one-day record of 962 deaths despite recent restrictions that shut most stores, tightened the rules on social contacts and urged people not to visit relatives over Christmas.

📈 Today's numbers: The U.S. has more than 18.4 million confirmed coronavirus cases and 325,500 deaths, according to Johns Hopkins University data. The global totals: More than 78.5 million cases and 1.72 million deaths. 

Here's a closer look at today's top stories: 

NYC orders foreign visitors to quarantine; UK extends restrictions to fight off new variant

New York City on Wednesday started requiring visitors from abroad to quarantine to ward off against the new coronavirus variant found in the UK. The order comes with the threat of a $1,000 fine for violators and the possibility of getting a knock on the door from a sheriff's deputy.

"There's going to be a follow-up direct home visit or hotel visit from the sheriff's deputy to confirm they are following the quarantine," Mayor Bill de Blasio said.  "Or if they do not, they will be penalized."

Meanwhile across the Atlantic, the discovery of the new strain has prompted British authorities to extend Tier 4 restrictions — the strictest ones — to six million more people in the east and southeast of England starting Saturday. 

Health Secretary Matt Hancock also said another variant from South Africa has been found in the UK, where several areas moved up to Tier 2 or 3 restriction levels.

Having COVID likely protects against reinfection, studies show

People with antibodies from contracting the coronavirus develop protection from reinfection for up to six months or longer that's akin to getting a vaccine, two new studies show. The results not only portend well for the new COVID-19 vaccines but also represent good news for those who recover from the disease.

Researchers found that people with antibodies from natural infections were “at much lower risk'' of catching the virus again, said Dr. Ned Sharpless, director of the U.S. National Cancer Institute, adding that “it’s very, very rare” to get reinfected.

The National Cancer Institute study involved more than 3 million people who had antibody tests from two private labs in the U.S., while the other one tracked more than 12,500 health workers at Oxford University Hospitals in the United Kingdom. Both showed people who had produced antibodies were 10 times less likely to have a second infection.

CDC urges Americans to 'stay at home' as millions flock to airports

Millions of Americans are traveling ahead of Christmas and New Year’s, despite pleas from public health experts to stay home and avoid fueling the pandemic. An average of more than 1 million people per day have rolled through the nation's airports the last five days, around the same number that crowded airports for the Thanksgiving holiday. 

"Stay home to best protect yourself and others from #COVID19 this holiday season," the Centers for Disease Control and Prevention tweeted Wednesday. "Host a virtual holiday meal with friends and family, gather for a virtual gift exchange, decorate your home, or make festive crafts."

Jennifer Brownlee, 34, a fisherman from Bayou La Batre, Alabama, was flying from Tampa airport to Oregon to see her mother, who just lost a leg.

“My mom’s worth it. She needs my help,” Brownlee said. “I know that God’s got me. He’s not going to let me get sick.”

Vaccine buy should supply enough for 'every American who wants it by June'

The federal government has agreed to pay $1.95 billion for a second round of 100 million vaccine doses from Pfizer and partner BioNTech. The deal brought the total number of doses of that vaccine to be delivered to the U.S. to 200 million by July 31. Health and Human Services Secretary Alex Azar said in a statement that the latest deal can give people confidence “that we will have enough supply to vaccinate every American who wants it by June 2021.”

Pfizer’s vaccine was the first to gain authorization for emergency use from the Food and Drug Administration, and health care workers are already being vaccinated. A second vaccine developed by Moderna in cooperation with scientists from the National Institutes of Health also is now in use.

Contributing: The Associated Press