Risk of getting long COVID seems to be on the decline
The risk of long COVID appears to be on the decline.
The clue to this extraordinary possibility comes from tens of thousands of responses to U.S. Census Bureau questionnaires that show a shrinking percentage of COVID survivors reporting long COVID symptoms — the persistent, often debilitating effects of the illness that studies have historically shown in about 19% of COVID survivors.
Last June, the Census Bureau, in partnership with the National Center for Health Statistics, added questions about long COVID to their “Household Pulse Survey,” a mostly monthly online questionnaire begun in April 2020 to gauge the pandemic’s impact.
The survey defines long COVID as symptoms lasting at least three months after a coronavirus infection. About 200 symptoms have been identified, with deep fatigue, heart palpitations, neurological complications and digestive disorders among the most common.
An average of 58,794 COVID survivors nationwide responded to each of the nine long COVID surveys offered so far by the Census Bureau. A Chronicle analysis revealed a remarkable trend: a consistently lower rate of people in each survey reporting long COVID symptoms.
In June, 18.9% of respondents said they were “currently experiencing” long COVID. By the end of the year, that had dropped to 11.3%, and by February it had slipped to 10.8%.
In California, the percentage of people reporting current symptoms rose slightly in July and October but otherwise mirrored the national trend, dropping from 16.2% in June to 10.3% in February.
“Fascinating,” said Dr. Steven Deeks, a long COVID researcher at UCSF not connected with the surveys. “These trends seem consistent with the anecdotal experience we and others have had.”
Research shows that people can get long COVID whether their initial infection was severe or mild. Scientists point to three likely causes: bits of virus that remain hidden in the body, persistent inflammation caused by the coronavirus, and autoimmunity — when the body’s own immune system turns on itself. These, in turn, can wreak havoc in the body months or even years later.
But is the “ability of the virus to cause long COVID waning?” asked Deeks. “That is indeed a question posed by these data.”
It’s possible the survey results reflect that some people are recovering from long COVID. A large Israeli study published in January found that most COVID patients who had mild infections saw their lingering symptoms clear up within a year after getting sick.
Deeks and two other long COVID experts, at Stanford University and UC Davis, said the apparent decline in long COVID may be due to vaccination and evolution in the coronavirus variants that cause COVID.
Dr. Christian Sandrock, who co-founded the long COVID clinic at UC Davis, said he has seen a drop in long COVID referrals to his clinic.
One reason, he said, could be omicron and its offshoots. “Just as the omicron has more cold symptoms and less rates of severe disease and hospitalization” than earlier variants, it also appears to produce fewer longterm symptoms, he said.
A new study by Swiss researchers that will be presented at the European Congress of Clinical Microbiology and Infectious Diseases in April found that people infected with the omicron variant were less likely to report long COVID symptoms than those infected with the original delta strain. Those findings support results from previous studies that suggest omicron is less likely to cause long COVID than were earlier variants.
Sandrock also credited the COVID vaccine.
A recent review of research in the British Medical Journal, for example, found that COVID vaccination reduces the likelihood, severity and duration of long COVID.
Dr. Linda Geng, co-director of Stanford Medicine’s long COVID clinic, agreed that vaccines and the newer variants may be responsible for the Census survey findings .
However, she said, selfreported data like that of the census surveys has limitations because people may define long COVID differently.
Geng said she is still seeing plenty of new patients in her long COVID clinic.
“Even if the rate is lower, the total magnitude of the problem can still be significant if a large number of infections continue,” she said. “The only guarantee against long COVID is to not get COVID.”
According to federal data, U.S. coronavirus cases have dropped 40% in the past month. But there are still about 170,000 people getting the disease each week.
And among those who still suffer from long COVID there is enormous frustration at the lack of viable treatments.
Some evidence has emerged that Paxlovid, an oral antiviral medication used to treat COVID-19, can help reduce the risk of ending up with long COVID.
A November study of 56,000 people with COVID found that the more than 9,000 who took Paxlovid in the first five days of their infection had a 25% lower risk of long COVID symptoms. But the data from one study isn’t conclusive.
In a webinar last month, White House COVID-19 Response Director Dr. Ashish Jha told Bob Wachter, chair of medicine at UCSF, that data showing therapies like Paxlovid can reduce the risk of long COVID are “very observational.”
“I wouldn’t bank on it,” he said, though he noted that “clinically it makes some sense.”
Researchers at Stanford are hoping for more clear evidence. They are seeking candidates for a clinical trial to see if Paxlovid can treat long COVID once people already have it.