LOS ANGELES — The risk of developing long COVID — enduring, sometimes punishing symptoms that linger well after a coronavirus infection — has decreased since the start of the pandemic, a new study found, with the drop particularly evident among those who are vaccinated.
But the dip does not mean the risk of developing long COVID has vanished. And given the rise in new infections, particularly during periods like now, when data indicateÌýÌýeven a lower rate of prevalence means many Americans risk developing symptoms that can last months or years after their initial infection clears.
"We have people in the clinic here with long COVID, and they're significantly affected, and some of them are profoundly disabled," said Dr. Ziyad Al-Aly, chief of research and development at the Veterans Affairs St. Louis Health Care System in Missouri.
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The study, published Wednesday, July 17 in theÌýÌýfound that 10.4% of people who were infected early in the pandemic suffered from long COVID symptoms a year after their acute infection.
But during the Omicron era, which began in mid-December 2021 when that variantÌýÌýof the coronavirus circulating worldwide, 3.5% of vaccinated people suffered from long COVID a year after their infection, as did 7.8% of unvaccinated people.
"It's good news," said Al-Aly, a coauthor of the study. "Long COVID is on the descent. It's declining and has gone down over the course of the pandemic."
But it's still a concern that long COVID rates remain as high as they are, Al-Aly said, especially as COVID "is still affecting millions of people."
The study was based on health records held by the U.S. Department of Veterans Affairs, which had data on more than 441,000 veterans who were infected with the coronavirus between March 1, 2020, and Jan. 31, 2022, and monitored for a year after their infection to track whether they experienced long COVID. The other coauthors are Yan Xie and Taeyoung Choi, who are also affiliated with the VA St. Louis Health Care System.
Whenever someone is infected with the coronavirus, there is a chance they will develop long COVID — a catchall term used to describe a wide array of serious symptoms that can result in chronic disability, according to theÌý. Some individuals have suffered from long COVID continuously since they were infected in the pandemic's earlier days, while others have seen their symptoms resolve within months.
Long COVIDÌýÌýinclude fatigue that interferes with daily life, brain fog and post-exertional malaise, in which symptoms worsen with physical or mental effort. Long COVID can also cause a fast-beating or pounding heart, dizziness when you stand up, depression and anxiety.
Millions of American adults and children haveÌýÌýlong COVID.
There are a few potential reasons that long COVID is rarer than it once was.
First, the coronavirus — officially known as SARS-CoV-2 — has changed significantly since it was first identified inÌý. And as the study found, getting vaccinated reduced the risk of developing long COVID.
"Vaccines do two things: They first reduce the severity of infection," Al-Aly said.
Second, "they actually help your immune system get rid of the virus faster," Al-Aly said. "They enhance the ability of the immune system to clear the virusÌý… and so there is less virus to wreak havoc" on organs and bodily systems.
One leading theory of the root cause of long COVID is that the coronavirus persists in the body long after an acute infection is over, Al-Aly said. So, if getting a vaccine helps the immune system get rid of the virus faster, that could lessen the chance of developing the syndrome.
The severity of long COVID varies from person to person. Some might experience mild cognitive dysfunction or fatigue, but can still accomplish daily tasks like taking their children to school or walking the dog. Others can suffer such "debilitating fatigue that they're really, really, really profoundly disabled by it — they cannot get out of bedÌý…ÌýÌýtheir activities of daily living," Al-Aly said.
Long COVID can emerge, persist, resolve and reemerge over a period of weeks or months, according to the CDC.
There are other data suggesting that long COVID's incidence has declined since earlier in the pandemic. Based on survey data, the prevalence of long COVID among U.S. adults was 7.5% in early June 2022, but had decreased to roughly 6% in early January 2023, according to aÌýpublished last summer by the CDC. Since then, the "prevalence remained unchanged" to mid-June 2023, shortly before that report was published.
About 1 in 4 adults who reported having long COVID when surveyed said they had significant limitations on their typical activities, the report said.
COVID and long COVID remain a more significant public health threat than the flu. The CDC estimates that there have been at least 25,000ÌýÌýdeaths nationally since the start of October, compared with at least 46,000 COVID-19ÌýÌýreported over the same period. Updated death estimates for the past flu season will be available this autumn.Ìý
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