Viral Hepatitis A, 2007

In 2007, 94 cases of hepatitis A (1.8 per 100,000 population) were reported including one (1%) death. Sixty-one (65%) case-patients were residents of the metropolitan area, including 47 (50%) residents of Hennepin or Ramsey Counties. Forty-seven (50%) of the cases were male. Case-patients ranged in age from 1 to 89 years (median, 40 years). Seventy-two (77%) cases were white, four (4%) were black, three (3%) were American Indian, and one (1%) was Asian; race was unknown for 14 (15%) cases. The three cases in American Indians were the first reported in American Indians in Minnesota since 2002. The incidence rate of hepatitis A in American Indians declined steadily from 10.4 per 100,000 in 1999 to 6.0, 3.7, and 2.5 per 100,000, in 2000, 2001, and 2002 respectively, demonstrating the success of targeted immunization efforts initiated in 1999. Hispanic ethnicity was reported for nine cases (4.4 per 100,000).

A risk factor was identified for 74 (79%) of the 94 cases, 20 (27%) of whom had known exposure to a confirmed hepatitis A case. These persons became infected following exposure to a close contact, representing missed opportunities to administer immune globulin. Of the remaining 54 (73%) cases with a risk factor identified, 17 (31%) were associated with travel. Of these 17, 13 (76%) traveled to Mexico, Central, or South America, four of whom reported consuming raw oysters.

In 2007, there were eight outbreaks of hepatitis A. Forty-two (45%) cases of hepatitis A were outbreak-associated. The number of cases per outbreak ranged from two to 15. Of the eight outbreaks, three were common-source food-borne outbreaks, three were community outbreaks, and two occurred among contacts of hepatitis A positive international adoptees. Post-exposure prophylaxis (immune globulin [IG] or hepatitis A vaccine) is recommended to prevent hepatitis A in persons exposed and to prevent or control outbreaks. One restaurant-associated outbreak in Hennepin County accounted for 15 (16%) cases. One restaurant-associated outbreak in Murray County accounted for eight (9%) cases, three (38%) of whom were restaurant employees. In response to the restaurant associated outbreak in Murray County, over 2,200 patrons received IG at a mass clinic conducted by the Lincoln, Lyon, Murray, and Pipestone Public Health Services. One foodborne outbreak accounted for four (4%) cases and was associated with consuming raw shellfish in Mexico. Seven (7%) cases, including three (3%) personal care attendants, were associated with an outbreak in a home in Hennepin County. The source case in this outbreak was travel-associated. Two (2%) cases were associated with an outbreak among group home residents. An outbreak in a daycare included two (2%) cases. One outbreak associated with international adoptee accounted for two (2%) cases including the source of infection in the group home outbreak. The other international adoptee associated outbreak accounted for two (2%) cases.

Hepatitis A vaccine is now recommended for post-exposure prophylaxis of certain groups. Hepatitis A vaccine used for post-exposure prophylaxis gives longer protection than IG, is often more readily available, and is easier to administer.

• For up to date information see>> Hepatitis A
• Full issue>> Annual Summary of Communicable Diseases Reported to the Minnesota Department of Health, 2007