Hepatitis B (Acute)

The clinical case definition for all types of viral hepatitis is: "An illness with dite onset of symptoms, and jaundice or elevated serum aminotransferase levels." Laboratory confirmation of hepatitis B requires IgM anti-HBc-positive (if done) or HBsAg-positive, and IgM anti-HAV-negative (if done). Confirmed cases of acute hepatitis B must meet the clinical case definition and be laboratory confirmed. Chronic carriage or chronic hepatitis should not be reported as acute hepatitis B. In Maryland, individuals with HBsAg positive laboratory results, but for whom no clinical information is known, are not included in the reporting of acute hepatitis B cases.

A plasma-derived hepatitis B vaccine was licensed in 1981 but is no longer available in the United States. The two currently used recombinant vaccines were licensed in 1986 and in 1989. The vaccines are 80% to 95% effective in preventing infection or clinical hepatitis in those who receive the complete series of three properly spaced doses. The universal immunization of all infants against hepatitis B was recommended by CDC in November 1991, following the failure of an immunization strategy involving only high risk groups. Immunization for hepatitis B is not currently required in Maryland for school entry and data on immunization coverage in the state are not yet available.

Although the reported incidence of acute hepatitis B since 1969 has been higher in Maryland than in the United States, the shape of the curves are very similar, with increasing incidence through the 1970's peaking in the mid 1980's, followed by declining incidence. Incidence in the United States decreased 59% from 1985 through 1993. The disease remains a major public health concern, with about 3% of acute cases requiring hospitalization, and 250 deaths from fulminant hepatitis B, 800 from hepatitis B related liver cancer, and 4,000 from hepatitis B associated cirrhosis reported every year in the United States.

There has been a consistent decline in all age groups in the number of reported cases of acute hepatitis B in Maryland from 1989 through 1993. The decline in incidence in Maryland has been steeper than that in the United States as a whole, resulting in nearly equal incidence in the state and in the nation for 1993. Maryland's data on the probable source of infection is too incomplete (data on source available for 29% of the cases reported from 1989 to 1993) to draw conclusions about the likely reasons for the declining incidence. However, the CDC reports that the decline in the U.S. since 1985 "was caused by decreases in the number of cases reported among homosexual men between 1985 and 1989 (61%), and in the number among injecting-drug users from 1989 through 1992 (51%). These changes are thought to result from an increase in AIDS awareness,which has resulted in behavioral changes (e.g., safer sex and needle-using practices)." The reported incidence of acute hepatitis B in Maryland during the five year period was substantially higher in Baltimore City and in Dorchester County than in other jurisdictions.

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