Doctors from the Center for Disease Control and Prevention in Atlanta interviewed 56,000 people from Wichita, Kansas. Of those interviewed, over 3500 stated that they had been suffering from fatigue for over a month. Of that number, 46 were evaluated and found to suffering from chronic fatigue syndrome (CFS).
Nearly one-fourth of those with CFS had left their jobs because of the illness. The patients with CFS who kept their jobs earned approximately one-third less than they would have without the illness. This loss of productivity comes to about $20,000 per year for each person with CFS.
Extrapolating the number of CFS cases to the United States, and assuming that the disease occurs in the same percentage of the population nationwide, there are approximately 450,000 cases of CFS. This makes the cost of the disease approximately $9 billion.