The Centers for Disease Control and Prevention (CDC) released the results of a surveyTrusted Source in which Americans report receiving a diagnosis of myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS)Trusted Source.

According to the survey, over 1.3% of Americans say their doctor told them they have chronic fatigue syndrome. Based on the current U.S. population of 333 million, 1.3% of that figure equals about 4.3 million Americans.

The CDC’s previous estimate for Americans with CFS/ME was 836,000 to 2.5 millionTrusted Source people.

The CDC also reports that about 90% of people with the condition have not been diagnosed.

According to the agency, CFS/ME costs the United States economy approximately $17 to $24 billion annually in medical bills and lost income.

CFS and ME are two different terms for the same condition. “ME” gained popularity among physicians in the United Kingdom, while “CFS” was first used in the U.S. “CFS/ME” is the current term applied to chronic fatigue syndrome in the U.S.

The survey questioned 57,133 American adults in 2021–2022. People in the survey were asked if they had received a definitive diagnosis of CFS/ME or if they recalled having been told they had the condition by their physicians.

CFS/ME is generally described as being characterized by at least six months of profound tiredness.

The rise in CFS/ME cases may be partially attributed to long COVID, a general term for the lingering effects of an acute COVID-19 infection.

A 2023 review found that CFS/ME and long COVID-triggered chronic fatigue are similar, though some differences exist. One international surveyTrusted Source found that 86.7% of respondents who had not recovered from long COVID reported chronic fatigue.

Dr. David Cutler, a family medicine physician at Providence Saint John’s Health Center in Santa Monica, CA, described the precise parameters of CFS/ME as somewhat vague. Dr. Cutler wasn’t involved in the survey.

“While the existence of chronic fatigue syndrome, or what is more accurately termed chronic fatigue syndrome/myalgic encephalomyelitis, is clear,” he said, “the actual definition of this condition is a little more confusing.”

Dr. Cutler added there are “multiple definitions” for chronic fatigue syndrome.

The CDC survey included the following key findings:

• Women are more likely to report CFS/ME than men, 1.7% versus 0.9%.
• CFS/ME cases were more likely in rural areas, with the most rural areas having the most cases.
• Adults in families with an income below 100% of the federal poverty level were more likely to have CFS/ME (2.0%) than those living at or abovethat economic level (1.1%). The higher a family’s income, the less likely its members were to have CFS/ME.
• White non-Hispanic adults were more likely to have the condition, at 1.5%, than Asian non-Hispanic people, 0.7%, and Hispanic people, 0.8%.

“Chronic fatigue syndrome is everywhere,” Dr. Cutler said.

“While it is interesting to try to interpret the demographic trends, it is more striking to note that this poorly understood condition is reported in 1%–2% of the population regardless of age, race, sex, income, or location.”