Half of people with long COVID improve within three years, but a particular subtype often lingers

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• What the study found
• Different outcomes by symptom subtype
• Who improved more — and who didn’t
• Link to ME/CFS and implications for trials
• Next steps for research

About half of people with long COVID experienced meaningful symptom improvement within three years of their initial infection, according to a new study — but recovery varied sharply by the symptoms patients had. The findings point to distinct long-COVID subtypes and could shape how future clinical trials are designed.

What the study found

Researchers followed roughly 1,020 adults enrolled in the NIH-funded RECOVER Adult Study, tracking symptoms with regular in-person visits and surveys every three months. Participants were included if they scored above 10 on a 30-point symptom measure called the 2024 LC Research Index (LCRI).

Investigators classified participants as “improved” when their LCRI fell to 10 or below at two consecutive visits. By two years after the infection that triggered their symptoms, 36% met that definition; by three years, the share rose to 50%. A quarter of the group — 26% — reported an LCRI of zero at three years, indicating no symptoms at the time of the survey.

Different outcomes by symptom subtype

Improvement rates were not uniform. About 60% of people whose main complaint was a loss or change in smell or taste saw substantial recovery after three years. By contrast, patients with symptoms affecting multiple organ systems fared much worse: only around 19% in that group showed meaningful improvement within the same period.

The study used an earlier RECOVER analysis that grouped long COVID into five subtypes based on predominant symptoms: loss of smell or taste, chronic cough, brain fog, heart palpitations, and multisystem presentations. Those in the last three categories were less likely to improve within three years, the authors report.

Who improved more — and who didn’t

Age and the viral strain also influenced outcomes. Adults younger than 46 were more likely to improve than older participants. People whose original infection involved Omicron variants were likelier to show recovery than those infected with earlier strains of SARS-CoV-2.

Study co-author Harrison Reeder, a biostatistician at Massachusetts General Hospital, emphasized caution about the word “recovered,” noting input from the long COVID community that symptoms can wax and wane. The study did not track whether individuals who improved later relapsed.

Link to ME/CFS and implications for trials

Some experts see overlap between long COVID and myalgic encephalomyelitis/chronic fatigue syndrome. Dr. Carmen Scheibenbogen, an immunologist at Charité University Medicine Berlin, said the multisystem group “looks as if at least a major subgroup is suffering from ME‑CFS,” suggesting COVID-19 may have triggered a similar illness in some people. “This is a disease which is triggered by different infections, but in the end, the disease [itself] is very similar,” she added.

Both Scheibenbogen and Reeder argued that recognizing these subtypes matters for designing clinical trials. Reeder suggested the multisystem group “might be a group where an effective intervention can make a bigger difference than people who stand to potentially have a higher chance of improvement regardless.”

Next steps for research

Authors say the findings should guide future work that digs deeper into biological differences among long-COVID subgroups, including studies of genes and proteins. “There’s a lot of work to do in RECOVER and in the world of long COVID research,” Reeder said. “There’s a lot of opportunity.”