RECOVER study finds COVID-19 increases risk of developing ME/CFS

A RECOVER study recently published in Journal of General Internal Medicine sheds new light on the relationship between COVID-19 and a condition called myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS). Like Long COVID, ME/CFS is a chronic (long-term) condition that may develop after an infection. 

People with ME/CFS frequently report extreme exhaustion and worsening of symptoms, lasting for days or weeks after exerting even a small amount of physical or mental effort. RECOVER research previously found 85% of patients with Long COVID reported this symptom as well. Both people with Long COVID and people with ME/CFS report that their symptoms may come and go over time. The similarities of these symptoms between these conditions suggest that researchers could study them to learn more about ME/CFS, Long COVID, and other infection-associated chronic conditions. 

Read the media advisory: NIH-funded study finds cases of ME/CFS increase following COVID-19

Read the study summary: Incidence and prevalence of post-COVID-19 myalgic encephalomyelitis: A report from the observational RECOVER-Adult study

What did researchers do?

Researchers studied whether having COVID-19 may increase a person’s risk of developing ME/CFS among participants in RECOVER’s adult observational study. This study includes thousands of people both with and without Long COVID, providing RECOVER researchers with an unprecedented chance to understand health conditions that occur after a viral infection. 

The study included 11,785 adults who had COVID-19. Participants in the study had:

• No prior history of ME/CFS.
• Taken part in a RECOVER follow-up visit at least 6 months after their initial SARS-CoV-2 infection.

The study also included 1,439 participants who did not have a history of COVID-19. 

As part of RECOVER’s observational study, participants complete standard forms answering questions about their symptoms, how sick their symptoms made them feel, and when they experience symptoms. Researchers used this information to identify new cases of ME/CFS, based on IOM clinical diagnostic criteria for ME/CFS. 

What did researchers find?

Researchers found that nearly 5 out of 100 people (4.5%) included in the study met ME/CFS diagnostic criteria after having COVID-19. Most of these people (nearly 89 out of 100 people, or 88.7%) also had Long COVID. In contrast, fewer than 1 out of 100 people (0.6%) who did not have COVID-19 met diagnostic criteria for ME/CFS. 

The study also found that:

• People who had COVID-19 were about 5 times more likely to meet diagnostic criteria for ME/CFS compared to those who did not have COVID.
• New cases of ME/CFS occurred at a rate 15 times higher than before the COVID-19 pandemic. 

Collectively, these findings suggest that having COVID-19 increases a person’s risk of developing ME/CFS.

The most reported ME/CFS symptoms were:

• Post-exertional malaise (PEM), or the worsening of symptoms after exerting even small amounts of physical or mental effort. 24% of study participants with ME/CFS after COVID-19 experienced PEM. PEM has also been found to be one of the most common and burdensome symptoms of Long COVID.
• Orthostatic intolerance, or a group of conditions that affect blood flow and can cause dizziness or fainting. This is related to postural orthostatic tachycardia syndrome (POTS), which is also a common Long COVID symptom.
• Cognitive impairment. This is similar to brain fog, or trouble thinking clearly, that some people experience with Long COVID.
• Unrefreshing sleep. People with Long COVID also sometimes experience trouble sleeping.

Why are these findings important?

These findings suggest that ME/CFS develops at an increased rate after having COVID-19 and that many people who develop ME/CFS also have Long COVID. 

This study also provides more information about the symptoms that Long COVID and ME/CFS have in common. People who experience these symptoms may want to ask their healthcare providers about being evaluated for ME/CFS. 

To learn more about the study and its findings, read the full publication in the Journal of General Internal Medicine.