Except for the internationally quarantinable diseases, no regulations require reporting of communicable diseases such as viral hepatitis in the United States. Practicing physicians voluntarily report viral hepatitis to their local health departments; however, for a variety of reasons, including inapparent infections and lack of interest, the cases represent only a small percentage of patients who develop the disease. Furthermore, no efforts are made to verify the physician's diagnosis by local, state, or federal officials. Despite these inherent defects, all states have reported viral hepatitis cases weekly since 1952, and consistent epidemiologic trends have emerged from analysis of the collected data nationally.
Figure 1 shows reported cases of viral hepatitis by quarter since July 1952. Incidence of viral hepatitis peaked in 1953 to 1954 and 1960 to 1961 and is believed to represent predominantly infectious hepatitis. Another peak in 1967 to 1968 was anticipated; however, it did not appear. On