Viral Hepatitis A, 2000

In 2000, 197 cases of hepatitis A (4 per 100,000 population) were reported. One hundred thirty-one (66%) cases were residents of the seven-county metropolitan area, with 100 (51%) residing in Hennepin or Ramsey Counties. Over half (57%) of the cases were male. Of the 189 cases for whom race was known, 144 (76%) were white, 33 (17%) were black, six (3%) were Asian, three (2%) were American Indian, and three (2%) reported some other race(s). Although the greatest number of cases were white, incidence rates were higher among blacks (19 cases per 100,000), American Indians (6 per 100,000), and Asians (4 per 100,000) than among whites (3 per 100,000). Hispanic ethnicity, which can be any race, was reported for 16 cases (11 per 100,000). Cases ranged in age from 3 months to 86 years; 65% of cases occurred among adults 20 to 64 years of age.

In 2000, 79 (40%) cases of hepatitis A were outbreak-associated. Of the five outbreaks investigated, three were common-source food-borne outbreaks, one occurred among homeless shelter residents, and one was a community outbreak. Four cases were associated with a food-borne outbreak at a private home in Washington County. A restaurant-associated outbreak in Ramsey County accounted for 38 cases, eight of whom were restaurant employees. In response to the outbreak, immune globulin (IG) was recommended for patrons. As a result, over 1,000 patrons received IG at two mass clinics conducted by the St. Paul-Ramsey County Department of Public Health. Because of the potentially large impact on transmission via food handlers, MDH recommends that food handlers be vaccinated against hepatitis A.

An outbreak in Mower County began with the infection of five family members and resulted in 13 additional cases. Two cases from the index family were food handlers. Eight hepatitis A cases (including one Hennepin County resident) were associated with a specific restaurant. Three cases were associated with child care or foster care settings. Two additional cases identified during this outbreak could not be linked to the restaurant or child/foster care. These cases may have been sporadic and identified because of heightened surveillance, or they may have had contact with asymptomatic or subclinical cases not identified during the outbreak.

An outbreak associated with homeless shelters in Hennepin County began in the summer of 1999 and continued into the spring of 2000. In 2000, seven shelter-associated infections were identified. The Hennepin County Community Health Department implemented a short-term hepatitis A prevention project in selected homeless shelters. Staff and residents 2 years of age or older were offered hepatitis A vaccine. Immunization rates of 39% (range, 32 to 46%) were achieved with one dose of hepatitis A vaccine. Since the initiation of the program, no new cases of hepatitis A have been identified among homeless shelter residents in Hennepin County.

Watonwan County experienced a community outbreak of hepatitis A in which 12 cases were identified in the community. Two cases had a history of travel to Mexico. Nine cases were clustered among three households. The source of the household clusters could not be determined but likely was due to transmission of hepatitis A virus from subclinical or asymptomatic cases (who most often are infants or children).

Of the remaining 118 sporadic cases of hepatitis A reported in 2000, a risk factor for infection could be identified for 74 (63%). Twenty-seven (23%) cases were associated with travel, 22 of whom traveled to South America or Mexico. Twenty-five (21%) cases had known contact with another case; ten (8%) cases were men who had sex with men, and one (1%) case had consumed raw shellfish. Ten (8%) cases (including nine children and one child care provider) were associated with child care settings but were not related to any known outbreaks. Thirty-seven (31%) of the sporadic cases occurred among persons for whom hepatitis A vaccine is indicated; one case reported both travel history and being a man who had sex with men. Persons who travel to hepatitis A endemic countries and men who have sex with men should be educated about their risk and offered hepatitis A vaccine.

• For up to date information see>> Hepatitis A
• Full issue>> Annual Summary of Communicable Diseases Reported to the Minnesota Department of Health, 2000