A person in a vehicle is tested with a swab at a drive-through covid-19 testing site operated by the District of Columbia. (Michael Reynolds/EPA-EFE/REX/Shutterstock)

Local officials and health experts say they worry that gatherings during Labor Day weekend — the first long weekend for students who have returned to classrooms across the country — could lead to a repeat of the national surge of coronavirus infections that followed Memorial Day if people don’t follow health guidelines.

This weekend presents challenges that didn’t exist earlier this summer, including schools resuming and a wider spread of infections overall, said Thomas Tsai, a researcher at the Harvard T.H. Chan School of Public Health, who partnered with Google to publish a forecast model for infections.

“In some ways we’re entering Labor Day with a more volatile mix than we did before Memorial Day,” he said. “We have masks and treatment, but we’re starting with a much higher base of cases, and we’re still seeing new hot spots rise across the country.”

Here are some other significant developments:

  • The novel coronavirus is the latest sign that the world has “entered a pandemic era,” immunologist Anthony S. Fauci and epidemiologist David Morens, both of the National Institute of Allergy and Infectious Diseases, warn in a report in the scientific journal Cell. The physicians write that human activity appears to be a major contributing factor in the emergence of diseases.
  • The U.S. unemployment rate fell below 10 percent for the first time since the pandemic began, though the recovery’s pace is slowing. After the announcement, the stock market plunged for the second straight day.
  • Northeastern University dismissed 11 first-year students who gathered in a hotel room in violation of the school’s social distancing guidelines and said the students’ tuition will not be refunded. Across the country, San Diego State University issued a stay-at-home order, asking students to remain in their dorms except for essential needs through the weekend, as the campus’s coronavirus case count rose to 184.
  • Moncef Slaoui, the chief scientific adviser for the Trump administration’s effort to accelerate production of a vaccine, told NPR on Thursday that it was “possible but very unlikely” that a vaccine would be available by late October or early November. President Trump contradicted him on Friday, saying a coronavirus vaccine would probably be available for distribution next month. And Tom Frieden, former director of the Centers for Disease Control and Prevention, said Saturday that “there are tough decisions coming up and people need to trust that we’re following the science.”

Infections swept through the Sun Belt after Memorial Day, straining health care systems in Texas, Florida, Arizona and other states as record numbers of people fell ill in those places. Tsai said the rise was attributable to a rushed reopening in Southern states where testing and contact tracing weren’t yet in place, inconsistent mask mandates and increased travel due to the holiday.

“It was a combination of all those factors,” Tsai said. “Which of those matters the most? It’s hard to say.”

States hit hard over the summer have reported progress in containing the virus in recent weeks, but new outbreaks have begun to surface in the Midwest. The Dakotas, Michigan and Minnesota have seen upticks in the positivity rate of their test results, which is a sign of accelerating cases, Fauci, the nation’s top infectious-disease expert, told CNN on Thursday. Additionally, per capita caseloads have risen most over the past week in North Dakota, South Dakota, Iowa, Missouri and Alabama, according to tracking by The Post.

“We don’t want to see a repeat of the surges that we have seen following the holiday weekends,” Fauci told CNN. “We don’t want to see a surge under any circumstances, but particularly as we go on the other side of Labor Day and enter into the fall.”

The CDC urged people who planned to attend gatherings on Labor Day to stay outside, wear masks, keep a distance of at least six feet from others and wash their hands often.

Trump on Friday told Americans to “remain vigilant” and “apply common sense.”

Many parts of the country also have restrictions in place that didn’t exist earlier this summer: Now, 34 states and the District of Columbia have universal mask mandates, up by 20 from Memorial Day weekend.

Last week, Alabama Gov. Kay Ivey (R) extended the state’s mask mandate through Oct. 2. Coronavirus infections typically spike during holiday weekends, but Labor Day will be the first holiday covered by the mask mandate in that state.

Scott Harris, Alabama’s state health officer, said he worried the mandate will be put to the test as Alabama residents make plans to celebrate the holiday.

“Labor Day has the opportunity to cause a lot of spread, if people aren’t careful,” he said in an Aug. 27 news conference with Ivey.

Rhode Island experienced an increase in reported infections after July 4, Gov. Gina Raimondo (D) cautioned in an emailed release.

“People got together in big groups. They had big parties and barbecues. They weren’t wearing their masks, and they weren’t practicing social distancing,” she said. “That’s not guesswork — we did extensive interviewing with people who tested positive to learn about where they contracted the virus. We know for a fact that because of that behavior, our daily case numbers jumped into the triple digits.”

In Florida, Gov. Ron DeSantis (R) projected optimism. At a news conference Monday, he said he expects the state to handle the Labor Day weekend better than Memorial Day, which saw spikes in infections after locals and tourists flocked to beaches.

“I think a lot of Floridians have really gotten into a good groove,” DeSantis told reporters. “You know, we’re open. We have stuff going on, they understand that. Schools [reopening] obviously a big part of that. You know, but they’re doing the basic things, and so I think If they continue to do that, I think we should be in good shape.”

Coronavirus: What you need to know

End of the public health emergency: The Biden administration ended the public health emergency for the coronavirus pandemic on May 11, just days after WHO said it would no longer classify the coronavirus pandemic as a public health emergency. Here’s what the end of the covid public health emergency means for you.

Tracking covid cases, deaths: Covid-19 was the fourth leading cause of death in the United States last year with covid deaths dropping 47 percent between 2021 and 2022. See the latest covid numbers in the U.S. and across the world.

The latest on coronavirus boosters: The FDA cleared the way for people who are at least 65 or immune-compromised to receive a second updated booster shot for the coronavirus. Here’s who should get the second covid booster and when.

New covid variant: A new coronavirus subvariant, XBB. 1.16, has been designated as a “variant under monitoring” by the World Health Organization. The latest omicron offshoot is particularly prevalent in India. Here’s what you need to know about Arcturus.

Would we shut down again? What will the United States do the next time a deadly virus comes knocking on the door?

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