Since August 2020, David Putrino, director of rehabilitation innovation at New York’s Mount Sinai Health System, has helped treat more than 3,000 people with Long COVID. These patients, in his experience, fit into one of three groups.
A small number, no more than 10%, have stubborn symptoms that don’t get better, no matter what Putrino and his team try. A big chunk see some improvement, but remain sick. And about 15% to 20% report full recovery – an elusive benchmark that Putrino greets with cautious optimism.
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“It’s really hard to tell” exactly how many people get over their symptoms entirely, says Dr. Ziyad Al-Aly, a clinical epidemiologist at Washington University in St. Louis who researches Long COVID. “But anecdotally, from clinical experience, the majority unfortunately don’t.”
Zeroing in on the Long COVID recovery rate is a work in progress, but two recent reports from the U.S. Centers for Disease Control and Prevention suggest remission is possible.
One, based on U.S. Census Bureau data, found that roughly 6% of U.S. adults currently have Long COVID, down from about 7.5% in the summer of 2022. The other found that many people’s symptoms disappear over time. A year post-infection, people who’d had COVID-19 were roughly as likely to have lingering symptoms as people who’d had other respiratory illnesses, the researchers found. That tracks with a January 2023 study in the BMJ, which found people who develop Long COVID after mild initial illnesses can expect most symptoms to improve within a year.
Other researchers, however, have come to less optimistic conclusions. In an August study published in Nature Medicine, Al-Aly and his team found people who’d had mild COVID-19 remained at increased risk of more than 20 Long COVID symptoms—including fatigue, gastrointestinal problems, and pulmonary issues—two years later. People whose COVID-19 was severe enough that they were hospitalized were at increased risk of more than 50 health problems two years later.
The findings reflect “the arduous, protracted road to recovery” for some people who catch COVID-19, Al-Aly says – a road that many people with Long COVID are still on, according to research posted online in July as a not-yet-peer-reviewed preprint. In a group of 341 people with Long COVID, only about 8% had fully recovered after two years of follow-up, co-author Dr. Lourdes Mateu and her colleagues found.
How can multiple studies on the same topic reach such different conclusions?
The way they’re designed can make a difference, Putrino says. Some Long COVID research uses data drawn from patients’ health records. In these studies, Putrino says, researchers sometimes assume symptoms have resolved if someone stops coming in for care. But there are lots of other reasons someone might stop seeing their doctor: financial constraints, frustration that treatments aren’t working, health declining to the point that leaving home becomes difficult, and so on.
“Recovery” can also be defined differently. Is it a complete resolution of symptoms, or improving enough that someone can function despite their ill health? Once researchers start splitting those hairs, Al-Aly says, they often find that someone “didn’t really recover; they adjusted to a new baseline.”
For that reason, research that takes into account patients’ own perceptions of their symptoms and recovery is important. That’s what Mateu and her team did. For two years, they tracked Long COVID patients who’d sought care at a hospital in Badalona, Spain, periodically asking about their symptoms during face-to-face visits and performing secondary diagnostic tests when necessary. With that level of scrutiny, Mateu says, the vast majority of patients did not meet their definition of recovery: the resolution of all persistent symptoms for at least three consecutive months…
In some cases, Mateu says, people with severe COVID-19 are left with issues that are significant but have better prognoses than Long COVID, such as post-intensive care syndrome. People who develop Long COVID after mild illnesses, by contrast, can be more vexing. Their test results may come back pristine yet their health remains poor, making it difficult for doctors to determine what to treat and how.