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According to the first large-scale study published on the long-term risks of ommicron, the chance that the ommicron variant will cause long-term COVID is much smaller than with delta.
But nearly 5% of people who receive omicron still experience fatigue, brain fog, headaches, heart problems or other health problems for at least a month after becoming infected, the study found.
While some researchers have found the results reassuring, others say the findings are alarming given that so many people have been given omicron and are apparently at risk even if they have been vaccinated.
“That’s scary,” said Dr. Akiko Iwasaki, an immunobiologist at Yale School of Medicine who has studied COVID for a long time but was not involved in the new research.
“People assume that because omicron is milder, that, you know, ‘let’s just get infected and be over it,’” says Iwasaki.
The findings, published Thursday in the lancetcome from researchers at King’s College London who have followed thousands of people who test positive for the coronavirus to determine the risk of long-term COVID from different variants.
“The basic question we’re trying to answer is, ‘Is COVID so common for a long time… in the delta period?’ [as it is] in the ommicron period?” said Dr Claire Steves, who helped conduct the study. “‘What is the risk of getting COVID for a long time, given the different variants?’”
The researchers compared 56,003 people who contracted omicron between December 20, 2021 and March 9, 2022 with 41,361 people who contracted delta between June 1, 2021 and November 27, 2021, and tracked their symptoms with a special app.
Those who took ommicron were about half as likely as those given delta to still experience health problems a month later, the researchers found.
“Fortunately, with the ommicron variant, the risk of contracting COVID for a long time is significantly reduced compared to the delta variant,” Steves told NPR in an interview. “That’s great news, isn’t it?”
It’s especially good news because omicron is so contagious that it has infected a huge number of people incredibly quickly. If the risk had been the same as delta or higher, the number of people who had long ended up with COVID-19 would have exploded.
The findings are consistent with a smaller analysis released recently by the UK government.
But lower risk doesn’t mean people don’t have to worry about long-term COVID because of ommicron, Steves and others agree. The chance of getting lung COVID from omicron is 4.4%, compared to nearly 10.8% from delta, the study said.
“The caveat is that the omicron variant has spread very quickly through our populations, and therefore a much larger number of people have been affected. So the total absolute number of people who will get COVID in the long run has unfortunately started to increase,” Steves said. . “So it’s definitely not time for us to cut back on services for a long time to COVID.”
But for each individual person, the findings indicate that the risk of both becoming seriously ill and developing persistent symptoms is significantly lower.
The study did not address why ommicron might pose a lower risk for long-term COVID. But Steves and others say it makes sense that omicron is less likely to lead to persistent symptoms because it doesn’t make people as sick as delta.
“Because of that lesser severity of the disease, and also because it seems to be a little more superficial in terms of the disease… it affects us less in terms of the severity of our immune response,” Steves says. “And therefore that leads to less chance of long-term COVID.”
Other researchers say these findings need to be confirmed by additional research.
“They just looked at everyone reporting symptoms through this app. They didn’t evaluate these patients in any clinic or collect objective data on them,” says Dr. Michael Sneller, who has long studied COVID at the National Institutes of Health.
But Sneller says he wouldn’t be surprised if ommicron is less likely to cause long-term COVID, as it appears to cause less serious illness.
Some researchers say they hope the findings will correct the misconception that people don’t need to worry about long-term COVID from ommicron.
“We say, you know, ‘You can take your masks off on airplanes. You don’t need to be vaccinated anymore to enter a restaurant.’ All of these policy decisions will increase the likelihood that people will become infected with COVID, while still having a 5% chance of developing serious chronic illness,” said Dr. David Putrino, who provides long-term treatment for COVID at Mount Sinai in New York City. “That’s short-sighted and will create a lot of long-term disabilities that didn’t have to exist.”