Over 90% of adult long-COVID patients in France gradually recovered over 2 years, while 5% improved rapidly, and 4% reported persistent symptoms, finds a study published late last week in the International Journal of Infectious Diseases.
Researchers in Paris analyzed data from a nationwide cohort on 2,197 patients reporting symptoms at least 2 months after a suspected or confirmed COVID-19 infection from December 2020 to July 2022. The vast majority of participants (90%) were enrolled before June 7, 2021, when the SARS-CoV-2 Alpha variant was dominant in France. Median follow-up was 291 days.
Participants completed online symptom questionnaires every 2 months, and the researchers used latent class mixed modeling to identify trajectories in long-COVID symptoms over time. Median patient age was 46 years, 79% were women, and 69% had confirmed COVID-19 infections.
Persistent symptoms and older age
A total of 90.8% of participants reported slowly decreasing symptoms, 4.9% said their symptoms were resolving quickly, and 4.3% said they had multiple symptoms that varied little over time.
Participants in the latter group were more likely to report tachycardia (abnormally fast heart rate), bradycardia (abnormally slow heart rate), heart palpitations, or abnormal heart rhythms (93%); paresthesia (burning or prickling sensations; 78%); hot flashes (76%); sweating (69%); heat or cold intolerance (65%); and sensitivity to light or sound (59%) in the first year after symptom onset.
This group was also older than those reporting slowly decreasing symptoms (odds ratio [OR], 1.04 per year) and more often reported smoking (OR, 1.49), a history of systemic illnesses (OR, 2.55), and no history of functional diseases (OR, greater than 10).
About half of the participants in this category reported daily symptoms with little change from symptom onset (54%) and at 18 months or later (53%). Some reported symptoms less than weekly from symptom onset (4%) to 18 months (10%).
Results could help project healthcare needs
Participants who reported rapidly resolving symptoms were more likely to report neck and back pain (65%) and diarrhea (52%) in the first year after infection. The proportion reporting symptoms less than weekly rose from 26% to 75% between symptom onset and at 18 months or more.
Our research is important for disentangling the underlying mechanisms of post COVID-19 assuming that different mechanisms (e.g. persistent inflammatory state, viral reservoir, autoimmunity, or psychological manifestations) could be associated with different evolutions.
Compared with those reporting slowly resolving symptoms, those saying their symptoms were rapidly resolving were more likely to have a confirmed COVID-19 infection (OR, 2.59), be current smokers (OR, 1.91), and have no history of functional diseases (OR, 2.96). In the group reporting slowly decreasing symptoms, the proportion with less-than-weekly symptoms climbed from 11% to 30% at symptom onset to 18 months or more.
"Our research is important for disentangling the underlying mechanisms of post COVID-19 assuming that different mechanisms (e.g. persistent inflammatory state, viral reservoir, autoimmunity, or psychological manifestations) could be associated with different evolutions," the study authors wrote. "Further research is required to link the trajectories identified with clinical and biological markers, which could help predict the membership of a given patient to a given trajectory."
They added that, from a clinical perspective, the findings could help estimate post-COVID healthcare needs and offer long-COVID patients evidence-based information on their prognosis.
