WWhen researchers began studying Long COVID, after it became clear in 2020 that some people do not recover from COVID-19 immediately, some estimated what about a third of people who contracted the virus experienced long-term symptoms.
But that was years ago, in a time before vaccines and endless iterations of Omicron, when most people had already been infected once, if ever. How has the risk of getting Long COVID changed over the years as the virus has evolved and nearly every person in the US has been vaccinated, infected, or both (sometimes many times)?
Recent research offers promising signs that Long COVID is becoming less threatening over time. But, experts say, there are still reasons for caution.
A studypublished on July 17th in New England Journal of Medicine, tracked a steady decline in the incidence of Long COVID from 2020 to 2022. Among people in the study who contracted COVID-19 during the Delta era, 5.3% of people who were vaccinated and 9.5% of those who were not vaccinated had Long COVID symptoms a year later. Among people who got sick during the Omicron era, those numbers fell to 3.5% and 7.8%.
These findings, based on health records from nearly 450,000 Department of Veterans Affairs patients who contracted COVID-19, are “good news,” says study co-author Ziyad Al-Aly, a clinical epidemiologist at the University School of Medicine. of Washington, in St. Louis. “The risk of Long COVID after SARS-CoV-2 infection has decreased over the course of the pandemic.”
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It’s impossible to say from the study whether the risk has continued to decline with each Omicron subvariant that has emerged since 2022, but Al-Aly says his hunch is yes. About 5% of U.S. adults say they currently have Long COVID, from the latest Census Bureau estimatedown from more than 7% in summer 2022.
Vaccination, which previous research shows can protect against Long COVID, appears to be an important explanation for the decline in Long COVID — a good reason to stay up to date with vaccines as new ones are released, says Al-Aly. But the evolution of the virus and advances in medical treatment, such as the use of the antiviral Paxlovid, may also have contributed, she says.
Other recent studypublished on July 11th in Communications Medicine, suggests another possible factor. Reinfections — which make up an increasing share of COVID-19 cases now that most people have had the disease — may be less likely to result in Long COVID than primary infections. (Al-Aly’s team did not evaluate the effect of reinfection in their paper.)
After analyzing the health records of about 3 million people included in RECOVER, the National Institutes of Health (NIH) Long COVID research project, researchers found that at each time of the pandemic, Long COVID was diagnosed with more frequently after the first rather than the second infection. . “The initial results are promising,” says study co-author Emily Hadley, research data scientist at the nonprofit RTI International.
But, experts say, no one should consider reinfections harmless. The study did not directly address a possibility that has been raised in some previous research, including some led by Al-Aly: that risks of complications, including heart, lung and brain damage, may accumulate with each additional infection, regardless of whether someone has or is not diagnosed with Long COVID.
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“All studies exploring reinfection risks should be done through the lens of cumulative risk,” says David Putrino, who is investigating Long COVID at New York’s Mount Sinai Health System but was not involved in any of the new studies. Putrino also notes that health records – the basis of both new studies – are imperfect data sources, as they do not capture the experiences of patients who do not seek health care, nor those who are not officially diagnosed with Long COVID.
Even when focusing on people who have been officially diagnosed with Long COVID, the new study on reinfections still raises some alarms, says Dr. David Goff, a member of the NIH’s RECOVER oversight committee. For him, the main conclusion is not that reinfections are less likely to result in Long COVID; is that some people still develop Long COVID, even after second infections.
“Even if you believe that the risk of developing Long COVID is somewhat lower after a reinfection than after the initial infection, it still exists,” says Goff. “It’s not zero.”
Likewise, even in the best-case scenario in Al-Aly’s study – vaccinated adults who contracted COVID-19 during the Omicron era – more than 3% still ended up with Long COVID, which potentially translates into millions of new cases nationally. .
Taken together, the studies suggest that changes in the virus, population immunity and medical care are reducing the risk of Long COVID, but not eliminating it completely. Whether to focus on good news or bad news largely depends on perspective and personal risk tolerance, says Akiko Iwasaki, an immunobiologist and Long COVID researcher at Yale School of Medicine who was not involved in any of the new studies.
Findings like these can be seen as cause for less concern. Or they could be seen as proof that Long COVID — while perhaps not the threat it once was — continues to affect new people all the time. “Knowing how devastating Long COVID can be,” says Iwasaki, “I tend to be more cautious.”
This story originally appeared on Time.com read the full story
