Occurrence of hepatitis A, B, and non-A/non-B in the United States. CDC sentinel county hepatitis study I.

To determine the relative occurrence of hepatitis A, B, and non-A/non-B in the United States, serum samples and epidemiologic data were collected from patients with hepatitis in five selected counties. Overall, 41, 33, and 26 percent of the patients had hepatitis A, hepatitis B, and hepatitis non-A/non-B, respectively. The incidence, especially of hepatitis A, varied considerably. All three types of hepatitis occurred more frequently in those 15 to 44 years of age. Hepatitis A predominated in those less than 15 years of age and non-A/non-B predominated in those older than 44 years. There was a male predominance (65 to 62 percent) for hepatitis A and hepatitis B, but non-A/non-B occurred equally in both sexes. There was no seasonal pattern for any type. Risk factors for hepatitis A were previous contact with a patient with hepatitis (26 percent), homosexual (male) preference (15 percent), and day-care center contact (11 percent). For hepatitis B, risk factors included drug use (26 percent), previous contact with an infected person (22 percent), homosexual preference (12 percent), and a health-care occupation (12 percent). For hepatitis non-A/non-B, risk factors included drug use (16 percent), transfusion (12 percent), and previous contact with an infected person (12 percent). Previous hospitalization appeared to be a risk factor for both hepatitis B and hepatitis non-A/non-B.