States are racing to get Covid-19 vaccine supplies and distribution in order as the US Centers for Disease Control and Prevention warned Friday of more contagious variants of coronavirus potentially exacerbating the spread.
CDC officials implored Americans to continue with preventative measures against the coronavirus, while highlighting the variant first identified in Britain known as B.1.1.7.
The B.1.1.7 variant appears to more readily infect human cells and one CDC simulation of its transmissibility raised concerns that it could become the United States' most dominant form of coronavirus in March.
The CDC called for aggressive vaccine distribution to try to stem the tide. "Higher vaccination coverage might need to be achieved to protect the public," CDC researchers warned.
On Friday, more than 3,400 Covid-19 deaths were reported in the US, as the total death toll from the pandemic edged closer to 400,000. The nation also recorded its 11th consecutive day of more than 200,000 infections, per Johns Hopkins University data.
At least 12.2 million doses of Covid-19 vaccines have been administered in the US as of Friday, according to the CDC, as the federal vaccine rollout has received intense scrutiny and criticism from state officials.
Some states were upset by news from Health and Human Services Secretary Alex Azar, who said Friday there is no "reserve stockpile" of vaccines available to release.
"We now have enough confidence that our ongoing production will be quality and available to provide the second dose for people, so we're not sitting on a reserve anymore," Azar told NBC News' Lester Holt. "We've made that available to the states to order."
Vaccine supply woes
Colorado Gov. Jared Polis said Friday he is "extremely disappointed that we were lied to" about the reserve vaccines, and that the next vaccines "will be delivered in the future of the supply chain."
"There is no influx of doses, contrary to a call we had with the Vice President [and] the Secretary of Health three days ago, where they informed us we would be getting an additional quantity available to the states," the governor said.
Polis estimated that of the 58,000 remaining doses in Colorado, "they will likely all or almost all be used by Sunday."
Governors from Michigan, Wisconsin and Minnesota wrote to Azar, critical of federal plans and hopeful they could purchase vaccines from manufacturers directly.
"Without additional supply or authorization to purchase directly, our states may be forced to cancel plans for public vaccination clinics in the coming weeks, which are expected to vaccinate tens of thousands. It's time for the Trump administration to do the right thing and help us end this pandemic," the letter states.
Pfizer on Friday tried to reassure state leadership and the public about production of its vaccine, saying it didn't anticipate any interruptions in shipments.
"Operation Warp Speed has asked us to start shipping second doses only recently. As a result, we have on hand all the second doses of the previous shipments to the US. We are working around the clock to produce millions more each day," Pfizer said in a statement to CNN.
In some metropolitan areas, including Houston, Phoenix and Los Angeles, stadiums and theme parks are being used as mass vaccination sites for eligible recipients.
In Los Angeles, about 2,200 people were vaccinated at the drive-through site outside Dodger Stadium on Friday, the first day vaccines were distributed there, Los Angeles fire spokesman David Ortiz said.
That site generally is vaccinating only health care workers for now, adhering to Los Angeles County rules aiming to inoculate medical personnel before making more people eligible.
A long line of vehicles snaked around the parking lot Saturday morning. The site eventually is expected to serve more than 12,000 per day, officials have said. The fire department partnered with other groups, including the CORE nonprofit founded by actor Sean Penn, to establish and staff the site.
"(I) talked to a captain who had two hours of sleep, trying to ... set up the logistics part of this huge (undertaking) here. And ... he has a smile on his face because he's doing everything he possibly can, humanly, to make (this) a success, to make this efficient," Oritz said.
January on pace to be the county's deadliest month of the pandemic
Covid-19 hospitalizations nationwide are near record levels, pushing some medical centers past normal capacity and straining their ability to give immediate care.
More than 127,200 Covid-19 patients were in US hospitals Friday, just a few thousand short of the highest mark set nine days earlier, according to the COVID Tracking Project.
While December was the country's deadliest month of the pandemic, January is on pace to be worse.
More than 46,240 US coronavirus deaths were reported in January's first 15 days. That's already more than half the roughly 77,500 recorded in all of December, according to Johns Hopkins data.
A recent coronavirus projection from the University of Washington estimates 566,720 deaths by May 1 in the US.
The university's Institute of Health Metrics and Evaluation (IHME) said the figure could be lowered by about 32,000 deaths with universal mask requirements.
Mask restrictions continue to fluctuate by state
Mask requirements are strongly urged by health officials to slow the spread of the coronavirus, and its implementation is expected to have a direct effect on future infections and deaths. State and local responses have varied widely. Some states continue to maintain no mask directives, allowing businesses to set their own rules.
On Friday, Mississippi extended its mask-wearing mandate in all but nine counties until February 3.
"It is important that we continue to take this virus seriously. We are working on getting Mississippians vaccinated, but continue to social distance, keep gatherings small and wear your mask," Gov. Tate Reeves said.
North Dakota, however, said officials are seeing its Covid-19 numbers falling from an earlier outbreak and Gov. Doug Burgum said the mask mandate will be allowed to expire on Monday, reiterating at a news briefing, "We must remain vigilant."
North Dakota capacity limitations for bars, restaurants, and event venues will be modified from requirements to recommendations.
CNN's Maggie Fox, Jason Hanna, Paul Vercammen, Devon Sayers, Amanda Sealy, Kay Jones, Hollie Silverman and Rob Frehse contributed to this report.