As Thanksgiving approached, Americans were bombarded with warnings that holiday travel and gatherings would bring a "surge on top of a surge" — setting the country on a precarious path as it entered the next round of holidays in late December.
Three weeks later, many places are now contending with a wave of infections that local health authorities say were fueled by the Thanksgiving holiday, although some regions appear to have evaded a dramatic rise, at least so far.
"We are seeing a tremendous surge in cases in many locations around the United States that are associated with the Thanksgiving dinners, family get-togethers and social events," says Michael Osterholm, an epidemiologist and director of the Center for Infectious Disease Research and Policy at the University of Minnesota.
Much of the evidence comes from health departments that are tracing clusters of cases, but Osterholm suspects that hospitalizations and deaths — "lagging indicators" — will reveal the full impact in a few more weeks.
In the Texas capital of Austin, public health authorities said that Thanksgiving drove a surge of new infections that risks overwhelming hospitals. Massachusetts Gov. Charlie Baker has urged residents not to "have a repeat" of Thanksgiving in the next round of holidays. And California — where cases have shot up a staggering 150% over the past two weeks — appears to be in the throes of a surge that is at least partly linked to Thanksgiving.
But even though the nationwide picture is mixed, Osterholm urges caution for the Christmas and New Year's holidays.
"No one's trying to take Christmas away from anyone," says Osterholm, "but we don't want our future Christmases eliminated because somebody became infected and died. And that is exactly the experience we're seeing off of Thanksgiving. So please take that as a hard lesson."
In Philadelphia, cases were falling before the holiday and about five days later daily case numbers jumped by about 50%, says Dr. Thomas Farley, health commissioner for the city of Philadelphia.
His department found many examples of families and friends getting infected after sharing a meal together, including the case of one woman who started to develop symptoms the day before having 10 people over to celebrate.
"By the time we caught up with her early next week, seven of those 10 guests were now testing positive," Farley says. "Multiply that even a few hundred times across the city, that's enough to drive an entire epidemic."
With cases so widespread, the country is essentially a sea of small outbreaks, with each community on its own trajectory, says Ellie Murray, an assistant professor of epidemiology at the Boston University School of Public Health.
The U.S is breaking daily records and hospitals are fuller than they've ever been in the pandemic, but it's too early to know exactly how much of that can be linked to Thanksgiving, says Murray.
"We're reasonably in a position where we can say that the really massive tsunami of cases didn't happen and that suggests the precautions people took, on average, were pretty good," says Murray.
A month ago, before Thanksgiving, the U.S. averaged about 163,000 new cases a day. The U.S. is now averaging more than 215,000 new cases a day. Some states with dire outbreaks in November put mask mandates in place just before Thanksgiving and have seen the pandemic slow down since then. Iowa, for instance, started a mask mandate on Nov. 17. In mid-November, Iowa reached an average peak of nearly 5,000 new daily cases but that has now dropped to just under 1,600 new cases a day.
"It looks from the data that we're in some middle place; it wasn't as bad as it could have been, it wasn't as good as it could have been," Murray says.
Doctors see the frightening fallout from Thanksgiving firsthand
It was about 10 days after Thanksgiving when Vishnu Chundi, an infectious disease physician in Chicago, started to see the aftermath of the holiday in his hospital.
In one case, a retired nurse he knew, as well as her husband and two children, all got infected after a dinner gathering.
"She didn't think this could happen to her and yet it did. And that's the take-home point for all of this," says Chundi, who chairs a COVID Task Force for the Chicago Medical Society. The nurse's husband and children survived; his former colleague did not. "It just broke my heart when she died."
Chundi says there are "innumerable examples" among his clinical colleagues of families who had visitors over for Thanksgiving dinner and ended up getting sick.
"This is unnecessary, and it's sad to watch people who still have a lot of quality life left being taken away by this virus," he says.
At his hospital in Washington state, Dr. Nathan Schlicher is also seeing patients who appear to have contracted the virus during a multigenerational Thanksgiving gathering.
"I took care of a 3-month-old last night that had been together with grandma, and grandma had COVID," he says. "Unfortunately the 3-month-old now has COVID."
Schlicher shares the temptation to see his parents and sisters over the Christmas holidays, but he won't do it.
He actually got the first dose of the COVID-19 vaccine this week, but he has no plans to change his behavior.
"I could still get the disease and it doesn't change the fact that the rest of my family isn't vaccinated."
One day can "change the entire course"
While it's hard to draw conclusions nationally, some local and state health departments report that the Thanksgiving holiday clearly ushered in a new infection within their communities.
"There is no question in my mind that we now know from Thanksgiving that get-togethers on a single day can change the entire course of the epidemic," says Farley, the Philadelphia health commissioner.
On Long Island, a surge emerged within a week of Thanksgiving — in much the same way it did after Halloween, says Dr. Gregson Pigott, Suffolk County commissioner of health.
"That's the frustrating thing, we're trying to do our best to control the pandemic, to keep a lid on it, but despite our best efforts the numbers are going up," he says.
Daily cases jumped from around 600 to about 900 starting in early December and infections have not slowed down since, he says. The spike came even after public advisories and media coverage called on people to limit gatherings to immediate members of a household and to avoid travel.
"I see all these messages out there, but we can't control human behavior," Pigott says.
Not all states suffered the same fate. Some states believe they may have dodged a post-Thanksgiving surge.
In other places, it's possible the holiday did not make a big difference because there are many other events driving infections.
Dr. Karen Landers, assistant state health officer for the Alabama Department of Public Health, says her state is finding some cases related to the holiday.
"But we were already in an upward trend, so it's just another event on top of an upward trend," she says.
This story is from NPR's partnership with Kaiser Health News.