New results from the National Institutes of Health’s Researching COVID to Enhance Recovery (RECOVER)-Adult Initiative suggest that 4.5% of COVID-19 survivors have myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS), compared with less than 1% of their uninfected counterparts.
ME/CFS, which can be triggered by viral and non-viral infection, causes severe fatigue for at least 6 months and may entail impaired memory, brain fog, dizziness, and muscle or joint pain. Physical or mental activity exacerbates symptoms, which aren’t fully relieved by rest.
RECOVER-Adult is a longitudinal observational study conducted at 83 sites in 33 states, Puerto Rico, and Washington, DC, to research post-COVID conditions such as ME/CFS and long COVID.
Participants, who reported symptoms at 3-month study visits, were grouped as: (1) acute infected, enrolled within 30 days of infection or were infected after enrollment (4,515); (2) post-acute–infected, enrolled more than 30 days after infection (7,270); and (3) uninfected controls (1,439) from October 2021 to September 2024.
Post-exertional malaise most common symptom
The percentage of all participants who had ME/CFS post-infection was 4.5%, compared with 0.6% of controls. Post-exertional malaise was the most common symptom in both acute-infected (15.9%) and post-acute–infected participants (29.1%), followed by positional dizziness (14.4% and 25.0%, respectively).
Acute-infected participants reported unrefreshing sleep (11.0%), “brain fog” (10.1%), and fatigue (9.3%) at similar rates, while post-acute–infected participants most often reported brain fog (23.7%), fatigue (20.7%), and unrefreshing sleep (19.8%). All ME/CFS symptoms were lower in controls than in infected participants. Most participants with post-COVID ME/CFS (88.7%) also had long COVID.
Of infected participants, 39.8% had ME/CFS-like conditions, with at least one ME/CFS symptom, while 55.7% didn’t report symptoms. Among uninfected participants, 16.1% had at least one ME/CFS symptom, and 83.3% had no symptoms.
The incidence of ME/CFS in participants after COVID-19 infection was 2.66 (95% confidence interval [CI], 2.63 to 2.70) per 100 person-years, compared with 0.93 (95% CI, 0.91 to 10.95) per 100 person-years in matched controls (attributable risk, 1.74 per 100 person-years; hazard ratio, 4.93).
White, unvaccinated women at highest risk
Relative to infected participants never meeting ME/CFS criteria, those with post-COVID ME/CFS were more likely to be White, women, 46 to 65 years old, and living in a rural area. They were less likely to have been vaccinated at enrollment and to have a college degree.
RECOVER provides the opportunity to identify objective biomarkers and to study the biology, mechanisms, and natural history of post-COVID-19 ME/CFS.
Because only nine uninfected participants had ME/CFS, the sample size was too small to compare with the other uninfected groups.
Participants with post-COVID ME/CFS were more likely to report chronic pain syndrome or fibromyalgia, neuromuscular disease, chronic obstructive pulmonary disease, dementia or brain fog, postural orthostatic tachycardia syndrome, dysautonomia or autonomic dysfunction, movement disorders, mental illness, and use of oxygen at home than their uninfected peers.
“This research underscores the urgency for healthcare providers to recognize post-COVID-19 ME/CFS,” lead author Suzanne Vernon, PhD, research director at the Bateman Horne Center, said in a University of Utah Health news release. “Early diagnosis and proper management can transform lives.”