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The omicron variant is much less likely than delta to cause long COVID, according to the first published large-scale study of the long-term risks posed by omicron.
But nearly 5% of people who catch omicron still suffer from fatigue, brain fog, headaches, heart problems or other health problems at least a month after being infected, the study found.
While some researchers found the results reassuring, others say the findings are alarming, given that so many people have caught the omicron and apparently remain at risk even if vaccinated.
“It’s scary,” says Dr. Akiko Iwasaki, an immunobiologist at Yale School of Medicine who has long studied COVID but was not involved in the new research.
“People assume that because the omicron is softer, you know, ‘Let’s just get infected and be done with it,'” Iwasaki said.
The findings, published Thursday in The Lancetcome from researchers at King’s College London who followed thousands of people who tested positive for the coronavirus to determine the risk of long COVID from different variants.
“The fundamental question we’re trying to answer is, ‘Is COVID as common…in the delta period? [as it is] in the omicron period? “says Dr. Claire Steves, who helped conduct the research. “‘What is the risk of continuing to have long COVID, given the different variants?'”
Researchers compared 56,003 people who caught omicron from December 20, 2021 to March 9, 2022, with 41,361 people who caught delta between June 1, 2021 and November 27, 2021, and followed their symptoms at using a special device. application.
Those who caught the omicron were about half as likely as those who got the delta to still have health problems a month later, the researchers found.
“Fortunately, with the omicron variant, the risk of continuing to have long COVID is significantly reduced compared to the delta variant,” Steves told NPR in an interview. “That’s great news, isn’t it?
This is particularly good news because the omicron is so contagious that it has infected huge numbers of people incredibly quickly. If the risk had been the same as delta or higher, the number of people ending up with long COVID would have skyrocketed.
The findings are consistent with a more limited analysis published recently by the UK government.
But lower risk doesn’t mean people shouldn’t worry about long COVID because of omicron, Steves and others agree. According to the study, the probability of getting long COVID with omicron is 4.4%, compared to almost 10.8% with delta.
“The caveat is that the omicron variant has spread very rapidly through our populations, and therefore a much larger number of people have been affected. So the overall absolute number of people who are expected to continue to have long COVID, unfortunately, is expected to increase,” Steves says. “So now is definitely not the time for us to cut services for a long time COVID.”
But for any person, the results indicate a significantly lower risk of becoming seriously ill and developing persistent symptoms.
The study did not explain why omicron might pose less risk for long COVIDs. But Steves and others say it makes sense that omicron would cause lingering symptoms less frequently because it doesn’t tend to make people as sick as delta.
“Because of this lower disease severity, and also because it seems to be a bit more superficial in terms of disease…it affects us less in terms of the severity of our immune response,” says Steves. “And so that reduces the likelihood of a long COVID.”
Other researchers say these findings need to be confirmed with further research.
“They just looked at everyone who reported symptoms on this app. They didn’t actually assess these patients in a clinic anywhere or collect objective data about them,” says Dr. Michael Sneller, who studies for a long time the COVID at the National Institutes of Health. .
But Sneller says it wouldn’t surprise him if the omicron is less likely to cause long COVID because it appears to cause less severe disease.
Some researchers say they hope the results will correct the misconception that people don’t have to worry about omicron’s long COVID.
“We say, you know, ‘You can take your masks off on planes. You no longer need to be vaccinated to enter a restaurant. All of these policy decisions are going to increase the likelihood of people getting infected with COVID, when there is still a 5% risk of serious chronic disease,” says Dr. David Putrino, who treats long COVID at Mount Sinai in New York. York. “It’s myopic and it’s going to create a lot of long-term disabilities that didn’t need to exist.”