A three-year study of over 1,000 long COVID patients found that 50% showed improvement within three years of their initial SARS-CoV-2 infection. The research, published November 3 in Annals of Internal Medicine, tracked patients enrolled in the National Institutes of Health-funded RECOVER Adult Study.
Improvement rates varied sharply by symptom type. About 60% of patients whose main symptoms involved changes to taste or smell improved significantly. By contrast, less than 20% of those with multisystem symptoms, affecting the cardiac, nervous, and gastrointestinal systems, improved in that timeframe.
Researchers used a 30-point scale called the 2024 LC Research Index to measure symptoms including fatigue, brain fog, shortness of breath, and heart palpitations. They marked patients as improved when they scored 10 or below at two consecutive visits. After two years, 36% had improved; after three years, that figure reached 50%. Among those three-year improvers, 26% of all participants recorded zero symptoms.
Younger adults under 46 showed better improvement rates than older participants. Those infected with Omicron variants improved more readily than those infected with earlier strains.
Harrison Reeder, a biostatistician at Massachusetts General Hospital and study co-author, cautioned against calling patients "recovered," noting that symptoms can wax and wane. The study did not track whether patients who improved later relapsed.
Dr. Carmen Scheibenbogen, an immunologist at Charité University Medicine Berlin, noted that the multisystem subgroup's pattern resembles myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS), a poorly understood condition that often follows infection. Both Scheibenbogen and Reeder said these symptom subtypes should inform the design of future clinical trials testing long COVID treatments.