Another COVID wave hits U.S. as JN.1 becomes dominant variant

The United States is in the throes of another COVID-19 uptick, cementing a pattern of the virus surging around the holidays as doctors and public health officials brace for greater transmission after Americans return to school and work this week.

Coronavirus samples detected in wastewater, the best metric for estimating community viral activity, suggests infections could be as rampant as they were last winter. A smattering of health facilities around the country, including every one in Los Angeles County, are requiring masks again. JN.1, the new dominant variant, appears to be especially adept at infecting those who have been vaccinated or previously infected.

While photos of positive coronavirus tests are once again proliferating across social media, fewer people are going to the hospital than a year ago. The Centers for Disease Control and Prevention reported 29,000 COVID hospitalizations in the week before Christmas, the most recent data, compared with 39,000 the previous year. The agency has reported an average of 1,400 weekly deaths since Thanksgiving, less than half of the fatalities at the same point last year.

Even so, COVID remains one of the leading causes of death as well as the top driver of respiratory virus hospitalizations — worsening the strain on hospitals also seeing influxes of flu and RSV cases.

"Of the three major viruses, it is still the virus putting people in the hospital most and taking their life," CDC Director Mandy Cohen said in an interview Wednesday.

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Even mild cases can lead to the lasting complications inflicted by long COVID.

The CDC still recommends people isolate for five days after testing positive, though many Americans have stopped doing so and free tests are harder to come by, making it easier for the virus to keep spreading if people don’t know their cold is actually COVID.

“As with any public health advice, getting people to adhere to policies is always challenging,” said Simbo Ige, commissioner of the Chicago Department of Public Health who is urging residents to follow that guidance. “Appealing to people’s desire to be part of the solution to ending COVID or reducing the impact of COVID is what we have seen be most effective.”

Michihiko Goto, an infectious-disease specialist who has seen a modest uptick in COVID patients at the Department of Veterans Affairs in Iowa City, worries that the return of college students will seed more infection in the coming weeks.

The CDC guidance for isolation makes sense, he said, but the reality is that many people do not have the flexibility at work to do so.

"People without paid sick leave may not be able to [isolate] because they have to feed their families," he said.

While coronavirus cases have surged every winter since the pandemic began, the CDC says it is not yet considered a seasonal disease like influenza. The coronavirus fluctuates throughout the year, and the typical winter waves could be influenced by other factors such as holiday travel, cold weather pushing people indoors and the evolution of the virus. The JN.1 variant that is now the most common in the United States has significantly more mutations than its predecessors, which could explain why people who had dodged infections during the summer surge are getting sick.

"If you look at the different peaks in cases since the beginning of the pandemic, every one of them coincided with the emergence of a new variant," said Michael Osterholm, director of the Center for Infectious Disease Research and Policy at the University of Minnesota. "Too many people are attributing this to seasonality."

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Few Americans are staying up to date on their coronavirus vaccines to train their immune systems to keep up with an evolving virus. According to CDC estimates, just 19 percent of Americans have received the latest version of the vaccine that lab experiments show offer better protection against the JN.1 variant than the previous formula.

"That's not doing enough to suppress the virus from evolving, getting stronger and more evasive," said Jessica Malaty Rivera, an epidemiologist and senior science communication adviser at the de Beaumont Foundation, a public health organization.

Medical professionals and public health officials say they're facing growing skepticism of coronavirus vaccines, particularly among conservatives. The latest pushback came Wednesday from Florida's top health official, who urged people to stop receiving mRNA coronavirus vaccines, citing debunked claims that they could contaminate patients' DNA.

Mainstream health officials have encouraged vaccination, particularly for people older than 65, to minimize the damage caused by COVID waves.

Wastewater tracking by the firm Biobot Analytics shows that the most recent coronavirus levels were slightly lower than the same point last year, except in the Midwest. The difference could be driven by changes in vaccines and variants affecting how much virus people shed, said Marisa Donnelly, a Biobot epidemiologist.

Donnelly said wastewater data is best used as a warning sign when levels rise.

“Right now as I’m seeing really high rates of COVID-19 in wastewater, I start to worry about people who are immunocompromised or have risk factors that put them at greater risk of developing severe COVID,” Donnelly said.

While the CDC had flagged New York and New Jersey in mid-December as among the first states with the highest share of infections caused by the new variant and high respiratory virus levels, hospitals in those states say those trends did not translate to crises in their wards.

"It's not uncontrollable, and it's nothing like it was last year," said Cathy Bennett, president and CEO of the New Jersey Hospital Association.

Hospital leaders now talk about the coronavirus in the context of the broader respiratory virus season. RSV, most often seen in infants and toddlers in pediatric wards, has already peaked nationally. The flu season started later than normal and is now accelerating, with 136,000 emergency department visits for influenza last week compared with 79,000 for COVID.

Northwell Health, New York's largest health-care system, has seen a surge in people coming to the emergency room and outpatient facilities testing positive for the coronavirus, which was expected after Thanksgiving. Those patients are typically discharged quickly and rarely end up severely ill.

“If you are looking at very sick people in the ICUs, it’s more likely flu than COVID,” said Bruce Farber, an infectious-disease physician and the system’s chief of public health and epidemiology. “If you are looking at total population in the hospital with people with some respiratory illness, it’s overwhelmingly COVID.”

But the addition of COVID to the usual winter swirl of respiratory viruses has strained other hospitals - including in Minnesota, where wastewater levels increased tenfold in the week before Christmas.

"Every hospital that does pediatric care is saturated," said John Hick, an emergency physician at Hennepin Healthcare, in downtown Minneapolis, which has 25 pediatric beds.

For the past month, hospital officials across the state have held coordination calls three times a week to triage which facilities have pediatric beds and whether certain patients can be moved into adult units, Hick said. Last week, the hospital began requiring patients and clinicians to wear masks again when interacting.

On Hick’s last ER shift a few days before Christmas, half the patients had either COVID or the flu. He expects to see more COVID cases in the coming weeks, given low vaccination rates.

What’s most dismaying, he said, is that many of those cases are preventable.