What is prevalence?

Prevalence is a measurement of how many people are currently experiencing a condition. This differs slightly from lifetime prevalence, which describes how common it is to ever experience a condition. But ultimately, both forms of prevalence are an important component of understanding the burden of a disease on a population.

Estimating lifetime prevalence of ME/CFS

Calculating an approximate lifetime prevalence of ME/CFS involves combining the results of a few studies that evaluated the prevalence of pre-COVID ME/CFS, the lifetime prevalence of Long COVID, and the proportion of Long COVID cases that match ME/CFS criteria. Through the following steps, we estimate that 1 in 29 people will experience ME/CFS in their lifetime:

• Published research estimates pre-COVID prevalence of ME/CFS at 0.89% of the population. Globally, that is around 71.2 million people.
• The lifetime prevalence of Long COVID is estimated to be 409 million people, which is about 5.11% of the population.
• Research estimates that 51% of Long COVID cases match ME/CFS criteria, which is about 208.6 million people worldwide.
• Altogether, the lifetime prevalence of ME/CFS is therefore 279,800,000 globally.

The table below summarizes these calculations globally and in three countries where OMF has an entity: the United States, Australia, and Canada.

Calculating prevalence based on pre-COVID ME/CFS and Long COVID matching ME/CFS symptoms likely gives a decent estimate. It’s possible it still doesn’t account for cases of ME/CFS that are misdiagnosed, though, which might come from other diseases that lead to ME/CFS symptoms, non-viral triggers, or other forms of the condition.

With hundreds of millions of individuals facing multisystem diseases like ME/CFS and Long COVID, OMF’s mission is to drive and fund global collaborative research that unlocks disease biology, delivers precise diagnostics, and advances treatments—giving every patient a pathway to care and hope. Read more about the research we do on our website.