Viral Hepatitis B, 2003

In 2003, 55 cases of acute hepatitis B virus (HBV) infection (1.1 per 100,000) were reported, including two deaths. Forty-three (78%) of these cases had clinical symptoms; the remaining 12 had documented asymptomatic seroconversions. Thirty-nine (71%) case-patients were residents of the Twin Cities metropolitan area, including 27 (49%) in Hennepin County. Thirty-six (65%) case-patients were male, and 35 (64%) were adolescents or young adults between 13 and 39 years of age. Twenty-seven (49%) were white, 15 (27%) were black, six (11%) were Asian, and three (6%) were American Indian; race was unknown for four (7%). Hispanic ethnicity was reported for four (7%) cases. Although the majority of cases were white, incidence rates were higher among blacks (7.4 per 100,000), American Indians (3.7 per 100,000), Asians (3.6 per 100,000), and Hispanics (2.8 per 100,000) than among non-Hispanic whites (0.6 per 100,000).

Thirty-eight (69%) of the 55 case patients were interviewed regarding possible modes of transmission. For 26 (68%) of these cases, the likely mode of transmission was sexual. Eleven (29%) case-patients were men who reported having sex with men, seven (18%) were persons who reported heterosexual contact with a known carrier of HBsAg, six (16%) reported heterosexual contact with multiple partners within 6 months prior to onset of symptoms, and two (5%) reported having multiple partners with undocumented sexual preference. Four (11%) case-patients reported using needles to inject drugs, and one occurred in a person who received a tattoo within 6 months prior to onset of cases and the 17 who were unavailable for interviews were between 13 and 72 years of age (median, 36 years).

Hepatitis B vaccine has been available since 1982, yet it continues to be underutilized in persons at greatest risk of infection. The majority of hepatitis B cases reported in 2003 with an identified risk factor indicated likely sexual transmission; therefore, health care providers should discuss the need for HBV testing and vaccination with at-risk patients, including all unvaccinated adolescents, young adults, and patients seen for other sexually transmitted diseases.

In addition to the 55 reported cases, six perinatal infections were identified in infants who tested positive for hepatitis B surface antigen (HBsAg) during post-vaccination screening. Five perinatal cases were identified in 2002, and one in 2001. Five perinatal infections occurred in infants identified through a public health program that works to ensure appropriate prophylactic treatment of infants born to hepatitis B-infected mothers, and one occurred in an infant adopted from an endemic region who arrived in Minnesota with an incomplete immunization history. All five U.S.-born infants had received hepatitis B immune globulin (HBIG) and three doses of hepatitis B vaccine in accordance with the recommended schedule (i.e., were treatment failures). These cases were identified in postvaccination serologic testing performed at 9 to 15 months of age.

• For up to date information see>> Hepatitis B
• Full issue>> Annual Summary of Communicable Diseases Reported to the Minnesota Department of Health, 2003