As we creep up on the fifth anniversary of the COVID-19 pandemic, we’re still learning just how much it’s changed our lives.
The latest lesson comes from the Researching COVID to Enhance Recovery (RECOVER) initiative, which has published research that shows that myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) could crop up at much higher rates following a COVID infection.
This new data reiterates, once again, the long-term health implications of COVID-19. It also provides fresh insight into the post-acute sequelae of SARS-CoV-2 infection (PASC), or long COVID.
Methodology
The RECOVER-Adult study, funded by the National Institutes of Health, is a national, longitudinal observational cohort study. Researchers wanted to pin down the incidence and prevalence rates of ME/CFS among adults with varying timelines of COVID infection.
Participants included:
- More than 4,500 individuals enrolled within the first 30 days of acute infection.
- 7,270 individuals enrolled more than 30 days after infection.
- And 1,439 uninfected participants.
None of the participants received an ME/CFS diagnosis before this study.
Finally, the study used the 2015 Institute of Medicine (IOM) clinical diagnostic criteria for ME/CFS, which includes constant fatigue, post-exertional malaise (PEM), and a lack of meaningful sleep, alongside cognitive impairment or orthostatic intolerance (OI).
The Results
The researchers found that the incidence rate of ME/CFS appeared to be much higher in those with SARS-CoV-2 infection – compared to uninfected participants. Among the individuals the study tracked since infection, 2.66 per 100 person-years developed ME/CFS, compared to 0.93 per 100 person-years in the uninfected cohort. The numbers reflect an increased risk of nearly fivefold.
Overall, 4.5 percent of RECOVER-Adult participants met the criteria for ME/CFS following COVID-19, compared to just 0.6 percent of uninfected participants. It’s worth noting that nearly 89 percent of participants with post-COVID-19 ME/CFS also met the criteria for long COVID, pointing to a strong overlap between conditions.
The researchers identified PEM as the most common symptom, affecting nearly a quarter of infected participants. Many individuals frequently reported cognitive impairment and orthostatic intolerance, which only added to the debilitating nature of ME/CFS.
ME/CFS prevalence among the general population (at least in the United States) before the pandemic ranged from 0.2 percent to 1 percent. The observed 4.5 percent post-COVID prevalence represents a startling increase, which echoes earlier studies that show a higher prevalence of ME/CFS in individuals with post-viral conditions. For example, the Innovative Support for Patients with SARS-CoV-2 Infections Registry (INSPIRE) reported a 3 percent to 4 percent prevalence among those with acute infection-like illnesses suggestive of COVID-19.
Biological and Clinical Implications
The study reinforces the working theory that ME/CFS is a post-infectious condition, with SARS-CoV-2 as the potential trigger. Earlier studies have hinted at links between infections like Epstein-Barr and Ross River to ME/CFS. And now this latest research implicates COVID-19 as well.
The mounting evidence points to structural, metabolic, and inflammatory brain irregularities, peripheral neurovascular dysregulation, and immune dysfunction as persistent underlying mechanisms of ME/CFS. Post-COVID-19 ME/CFS patients typically showed symptoms similar to the most symptomatic long COVID subgroup, backing up the suspected connection between the two conditions.
These study results reinforce the need for further research into the biology and natural history of post-COVID-19 ME/CFS. The study’s authors add that identifying objective biomarkers and developing targeted interventions could improve diagnosis and management.
Further Reading
Even Mild COVID Cases Leave Lasting Brain Changes in Young Adults
