Symptoms of long-term coronavirus infection subsided in about half of more than 1,000 patients within three years of their initial SARS-CoV-2 infection, according to a new study. Improvement varied substantially by symptom pattern: about 60% of patients whose main symptom was a change in taste or smell improved significantly, while fewer than 20% of those with symptoms affecting multiple body systems improved during the same period.
The study was published in the journal Science on Tuesday, November 3. Researchers said the findings could help shape future clinical trials for treatments for long-term coronavirus infection, also known as long COVID.
Tracking symptoms over three years
The patients were enrolled in RECOVER Adult Research, a National Institutes of Health-funded project that recruited thousands of adults across the United States who had previously tested positive for COVID-19.
Researchers evaluated symptoms including fatigue, brain fog, shortness of breath and heart palpitations. The study included nearly 1,020 patients who scored at least 10 points on the 30-point 2024 LC Research Index (LCRI), which was designed to capture the combined effects of these symptoms.
Participants attended in-person appointments every three months and completed symptom surveys. Researchers classified a patient as “improved” if their LCRI score was 10 or lower at two consecutive visits.
Thirty-six percent of participants had improved symptoms two years after their initial COVID-19 infection. After three years, that figure had risen to 50%. In addition, 26% of participants had an LCRI score of zero after three years, meaning all symptoms had disappeared at the time of the study.
Harrison Rieder, a study co-author, said he avoided describing the participants as “recovered.” That decision reflected input from the coronavirus community during the RECOVER Adult Study, whose members emphasized that symptoms can wax and wane, while “recovery” implies a permanent resolution. The study did not establish whether patients who improved later relapsed.
One disease, many symptom patterns
The course of the illness differed considerably depending on which body systems were affected. Men and women improved at similar rates, while adults younger than 46 were more likely to improve than older participants. People infected with the Omicron variant of SARS-CoV-2, which emerged in 2021 and quickly became the dominant strain, were more likely to improve than those infected with earlier variants.
The largest differences involved patients’ primary symptoms. In previous research, RECOVER scientists used an algorithm to group participants into five subtypes based on shared symptoms:
- loss of smell or taste
- chronic cough
- brain fog
- heart palpitations
- symptoms affecting multiple body systems
Patients in the last three groups were less likely to improve within three years. The rate was particularly low among people with multisystem symptoms, at just 19%.
Connections with ME/CFS
Dr. Carmen Scheibenbogen, an immunologist at Charité University of Berlin, told Live Science that the course of illness in patients with multisystem long COVID was similar to that of people with myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS).
“It appears that at least a major subgroup suffers from ME/CFS,” Scheibenbogen said, noting that COVID-19 may have caused their symptoms. “This is a disease caused by a variety of infections, but ultimately [itself] it’s very similar.”
Like long COVID, ME/CFS can affect multiple body systems. Despite recent research advances, it remains poorly understood.
Implications for clinical trials
The researchers said the findings highlight the need for clinical trials testing possible treatments for long-term coronavirus infection. Scheibenbogen and study co-author Harrison Rieder, a biostatistician at Massachusetts General Hospital, said the symptom subtypes should be considered when designing those trials.
Multisystem subgroups “may be the groups where effective interventions could make a bigger difference than those with a higher potential for improvement,” Rieder said.
Future research will need to clarify, at the genetic and protein levels, why some people develop long-term coronavirus symptoms. “There is a lot of work to be done in the world of RECOVER and long-term coronavirus research,” Rieder said. “There are a lot of opportunities.”
This article is for informational purposes only and does not provide medical advice.
Source: www.livescience.com