Experts worry a recent rise in long COVID cases — fueled by a spike in winter holiday infections and a decline in masking and other measures — could continue into this year.
A sudden rise in long COVID in January has persisted into a second month. About 17.6% of those surveyed by the Census Bureau in January said they have experienced long COVID. The number for February was 17.4.
Compare these new numbers to October 2023 and earlier, when long COVID numbers hovered between 14% and 15% of the US adult population as far back as June 2022.
The Census Bureau and the Centers for Disease Control and Prevention (CDC) regularly query about 70,000 people as part of its ongoing Pulse Survey.
It’s Not Just the Federal Numbers
Independently, advocates, researchers, and clinicians also reported seeing an increase in the number of people who have developed long COVID after a second or third infection.
John Baratta, MD, who runs the COVID Recovery Clinic at the University of North Carolina, said the increase is related to a higher rate of acute cases in the fall and winter of 2023.
In January, the percentage of North Carolinians reporting ever having had long COVD jumped from 12.5% to 20.2% in January and fell to 16.8% in February.
At the same time, many cases are either undetected or unreported by people who tested positive for COVID-19 at home or are not aware they have had it.
Hannah Davis, a member of the Patient-Led Research Collaborative, also linked the increase in long COVID to the wave of new infections at the end of 2023 and the start of 2024.
“It’s absolutely real,” she said via email. “There have been many new cases in the past few months, and we see those new folks in our communities as well.”
Wastewater Remains the Best Indicator
“This results in many cases of COVID flying under the radar,” Baratta said. “However, we do know from the wastewater monitoring that there was a pretty substantial rise.”
Testing wastewater for COVID levels is becoming one of the most reliable measures of estimating infection, he said. Nationally, viral measure of wastewater followed a similar path: The viral rate started creeping up in October and peaked on December 30, according to CDC measures.
RNA extracted from concentrated wastewater samples offer a good measure of SARS-CoV-2 in the community. In North Carolina and elsewhere, the state measures the virus by calculating gene copies in wastewater per capita — how many for each resident. For most of 2023, North Carolina reported fewer than 10 million viral gene copies per state resident. In late July, that number shot up to 25 million and reached 71 million per capita in March 2023 before starting to go down.
Repeat Infections, Vaccine Apathy Driving Numbers
Baratta said COVID remains a problem in rural areas. In Maine, wastewater virus counts have been much higher than the national average. There, the percentage of people who reported currently experiencing long COVID rose from 5.7% in October to 9.2% in January. The percentage reporting ever experiencing long COVID rose from 13.8% to 21% in that period.
Other factors play a role. Baratta said he is seeing patients with long COVID who have refused the vaccine or developed long COVID after a second or third infection.
He said he thinks that attitudes toward the pandemic have resulted in relaxed protection and prevention efforts.
“There is low booster vaccination rate and additional masking is utilized less that before,” he said. About 20% of the population has received the latest vaccine booster, according to the Kaiser Family Foundation.
The increase in long COVID has many causes including “infection, reinfection (eg, people getting COVID after a second, third, or fourth infection), low vaccination rates, waning immunity, and decline in the use of antivirals (such as Paxlovid),” said Ziyad Al-Aly, MD, chief of research at Veterans Affairs St. Louis Health Care and clinical epidemiologist at Washington University in St. Louis, St. Louis, Missouri.
“All of these could contribute to the rise in burden of long COVID,” he said.
Not all states reported an increase. Massachusetts and Hawaii saw long COVD rates drop slightly, according to the CDC.
