Hepatitis B (Acute)

The clinical case definition for all types of viral hepatitis is: "An acute illness with dite onset of symptoms, and jaundice or elevated serum aminotransferase levels." Laboratory confirmation of hepatitis B requires IgM anti-HBc (core)-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. 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, but will be required beginning September 1, 2000 for Pre-K programs. Data on immunization coverage in the state are not yet available.

Historical Trends (see graphs below)

Although the reported incidence of acute hepatitis B from 1969 to 1995 was higher in Maryland than in the United States, the shape of the curves is 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 61% from 1985 through 1997. The disease remains a major public health concern, with 15,000 to 20,000 cases reported each year, 3% of which require hospitalization. A total of 300-450 deaths result from fulminant hepatitis B, and 5,000 – 6,000 people die each year due to HBV-induced chronic liver disease.

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 1998. The decline in incidence in Maryland has been steeper than that in the United States as a whole, resulting in a lower incidence in the state than in the nation for 1998. However, an increasing number hepatitis B surface antigen reports in Maryland remain uninvestigated each year, indicating that the decrease observed for acute cases may not reflect an accurate trend.

Maryland's data on the probable source of infection is too incomplete (data on source available for 32% of the cases reported from 1989 to 1998) to draw conclusions about the likely reasons for the declining incidence. 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)."

Information was provided by 121 (85%) of the cases about exposures with potential risk for acquiring hepatitis B during the 6 months prior to their onset of illness. Sixty-nine (57%) of those reported the presence of one or more risky exposures; 50 reported a single risk factor while 19 reported multiple risk factors. The risk factors reported included multiple sexual partners (18), dental work or oral surgery (16), use of needles for injection of street drugs (14), contact with a confirmed or suspected case of hepatitis B (10), homosexual or bisexual orientation (8), tattooing (7), surgery (6), transfusion (5), an accidental stick or puncture with a needle or other object contaminated with blood (4), medical or dental field employee (2), association with a dialysis or kidney transplant unit (2), and acupuncture (1).

Figure 1. Hepatitis B Incidence by Jurisdiction. Reported Cases in Maryland, 1998.

Figure 2. Acute Hepatitis B Incidence. Maryland and United States, 1989-1998.

Figure 3. Reported Cases of Acute Hepatitis B in Maryland, 1971-1998.

Figure 4. Hepatitis B Incidence by Age Group and Gender. Maryland, 1998.

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