Viral Hepatitis B, 2000
In the year 2000, 58 cases of acute hepatitis B virus (HBV) infection were reported (1.2 per 100,000 population), with no deaths. Forty-six (79%) cases were residents of the seven-county metropolitan area, with 25 (43%) cases residing in Hennepin County. Forty-one (71%) cases were male. Thirty (52%) cases were young adults between 19 and 39 years of age. Twenty-eight (48%) cases were white, 13 (22%) were black, 10 (17%) were Asian, and one (2%) was American Indian; race was unknown for six (10%) cases. Although the majority of cases were white, incidence rates were higher among blacks (7.6 per 100,000), Asians (7.0 per 100,000), and American Indians (1.8 per 100,000) than among whites (0.6 per 100,000). Hispanic ethnicity, which can be of any race, was reported for two cases (1.4 per 100,000).
Of the 58 reported cases, 19 (33%) were patients with documented asymptomatic seroconversions, including six (10%) perinatal infections. These six infants tested positive for hepatitis B surface antigen (HBsAg) during post-vaccination screening. All six infants began hepatitis B immunoprophylaxis (i.e., hepatitis B immune globulin and HBV vaccine) at birth and completed the three-dose vaccine series. Four of these infants were age-appropriately vaccinated with second and third doses, and two were delayed in the receipt of one or more doses of vaccine. In 2000, the MDH received post-vaccination test results for 235 infants born to HBsAg-positive mothers.
Forty-nine (84%) of the 58 reported cases of HBV infection were interviewed regarding possible modes of transmission. For 18 (37%) cases, the likely mode of transmission was sexual. Six (12%) cases were men who reported having sex with men; four (8%) cases reported heterosexual contact with a known carrier of HBsAg; six (12%) cases reported heterosexual contact with multiple partners within 6 months prior to onset of symptoms, and two (4%) cases gave recent histories of sex with an HBsAg-positive partner with undocumented sexual preference. One (2%) case used needles to inject drugs. In addition to the six perinatal cases, five (10%) cases reported non-sexual contact with an HBsAg-positive person; these cases included two children recently adopted from outside the United States. No cases were reported as a result of occupational exposure. Risk factors for acquiring HBV infection were not identified for the remaining 19 (39%) cases who were interviewed. The median age among these 19 cases and the nine cases who were unavailable for an interview was 34 years (range, 20 to 67 years) which is consistent with possible sexual transmission.
MDH recommends HBV vaccination for all children and adolescents not previously vaccinated or infected with HBV. The Minnesota School Immunization Law requires HBV immunization for all children entering kindergarten and seventh grade. The vaccine also is recommended for all adults who are at increased risk of infection. Due to the continued high rate of sexually transmitted HBV infections, health care providers are encouraged to discuss HBV testing and immunization with at-risk patients.