In what is becoming a holiday-season tradition, Covid-19 cases are rising once again in the U.S., according to the Centers for Disease Control and Prevention.
Doctors and virus trackers expect cases to increase further in coming weeks as the weather gets colder and people gather indoors for the holidays. They are also closely watching a variant, JN.1, that is spreading fast around the world.
Covid-19 test positivity rates increased over the summer and then stabilized earlier this fall. They have recently ticked back up, rising 1.2% for the latest week, according to the CDC’s most recent data. Emergency department visits and hospitalizations are up about 10% over the same period.
Scientists and public-health officials say that data understates the current virus spread and point to elevated levels of the virus detected in wastewater. Wastewater levels are an early warning for infections, with levels up nationally since mid-October.
With the virus on the rise and uptake low for the latest Covid-19 shot, doctors’ advice to patients is to take precautions, such as masking on airplanes. They are also assuring them that this round of Covid isn’t the same as three years ago because most people have some level of immunity from previous infections and vaccinations.
Zahir Rasheed’s Thanksgiving started with turkey and the fixings and ended with a bout of Covid-19, his first.
Three days after the holiday, the 26-year-old Vienna, Va., resident tested positive for Covid-19, one of four members of his extended family to get it. Rasheed had a relatively mild case. He says he felt more sick than he has been in years but it lasted just a couple of days.
“Thanksgiving is also a time when a lot of people get it. I think I was just a victim of that and also not getting the Covid booster shot,” says Rasheed, a federal employee in D.C. who had gotten previous Covid-19 boosters before Thanksgiving but hadn’t yet this year.
Variant soup
Unlike previous Covid seasons, where one variant would cause a tsunami in cases, a soup of variants can result in a high sustained baseline of cases, says T. Ryan Gregory, an evolutionary biologist and professor at University of Guelph in Ontario.
While hospitals might not grow overwhelmed with Covid patients, the sustained cases could result in worker and student attendance, a demand in doctor’s visits, and other burdens as people prepare to see family around the holidays, says Gregory.
The CDC’s November forecast for Covid-19 predicts levels similar to last winter. That forecast was developed before the rise of JN.1, recently dubbed a variant of concern by the World Health Organization.
The variant is a descendant of the highly mutated BA.2.86 variant, which was dubbed “pirola” by some virus scientists. Pirola sparked concern this summer, but wasn’t ultimately a big driver of cases.
JN.1, on the other hand, is growing rapidly on a global level, says Jesse Bloom, a virologist and professor at Fred Hutchinson Cancer Center in Seattle. It has quickly spread in countries such as France and England. JN.1 has been detected in the U.S., though only as a blip.
Epidemiologist Katelyn Jetelina, a scientific adviser to the CDC and author of the “Your Local Epidemiologist” newsletter, says that while JN.1 isn’t growing as fast as the original Omicron in the winter of 2021-22, its current rate of growth could fuel a wave in Covid-19 cases.
“If that rate continues, we should see dominance in the U.S. around Christmastime, which means that it would really jump-start a wave around New Year’s,” she says.
The good news, says Bloom, is that research indicates the new booster—developed to protect against the XBB variants that were dominant this summer—appears to work for the more mutated newer variants, too.
“We have some optimistic data that the new booster is improving antibody [levels] to these newer variants but it’s certainly not perfect,” says Bloom.
Wastewater science
The new CDC national wastewater tracker has shown increasing viral activity in our waste since mid-October, with nationwide levels currently deemed “high.” There are five levels of wastewater distinction from the government, ranging from minimal to very high. High is one below very high.
Wastewater viral activity for Covid-19 is particularly high in the Midwest and Northeast, according to the site.
“Wastewater is literally the earliest indicator, a great tool to show community transmission and it’s one of the more comprehensive metrics we have,” says Jetelina, who was involved with developing the new CDC wastewater site.
Holidays like Thanksgiving and Christmas open up social networks that don’t always interact with one other, she adds. So people are exposed to friends and family members from other parts of the country they don’t regularly see, which can result in more virus transmission.
In addition, uptake of the new booster has been low, so many Americans will remain vulnerable. Only about 16% of adults and 7% of children have received the new booster, according to CDC data.
Write to Sumathi Reddy at Sumathi.Reddy@wsj.com
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