Viral Hepatitis A, 2004

In 2004, 59 cases of hepatitis A (1.2 per 100,000 population) were reported. Forty-five (76%) case-patients were residents of the Twin Cities metropolitan area, including 16 (36%) residents of Hennepin or Ramsey Counties. Thirty-one (53%) of the cases were male. Although the greatest number of cases (34, 58%) were white, incidence rates were higher among Asians (11.2 per 100,000) than among whites (0.8 per 100,000) or blacks (0.49 per 100,000). No cases were reported in American Indians in 2003 or 2004. The incidence rate of hepatitis A in American Indians declined steadily from 10.4 per 100,000 population in 1999 to 6.0, 3.7, and 2.5 per 100,000, respectively, in 2000, 2001, and 2002 demonstrating the success of targeted immunization efforts initiated in 1999. Hispanic ethnicity was reported for four cases (2.8 per 100,000). Case-patients ranged in age from one to 87 years.

Two (4%) case-patients were employees of food-serving establishments. No community transmission of hepatitis A was identified.

Of the 59 cases, a risk factor was identified for 35 (59%). Twenty-one (60%) had known exposure to a confirmed hepatitis A case. Four of these persons, in three separate families, became infected following exposure to a family member, representing missed opportunities to administer immune globulin. Sixteen persons were related to an outbreak associated with Hmong arrivals from the Wat Tham Krabok refugee camp in Thailand; 14 of these cases acquired their infection abroad, and two case-patients acquired their infection in Minnesota through contact with these refugee cases. One other case-patient was a household contact of a confirmed hepatitis A case while visiting Turkey.

Of the remaining 14 (40%) cases with a risk factor identified, 13 (93%) were associated with travel. Of these 13, six (46%) traveled to Mexico or South America, and two reported consuming raw shellfish. One additional case was a man who reported having sex with men (MSM). Twenty-four cases did not report any known exposure or risk factors; however, one had contact with a household member enrolled in a childcare center. Young children infected with hepatitis A are often asymptomatic or have mild illness, but are efficient transmitters of disease.

Hepatitis A vaccine is licensed for persons 2 years of age and older. Although all persons could potentially benefit from receiving hepatitis A vaccine, those who travel to hepatitis A endemic countries and MSM, in particular, should be educated about their increased risk of acquiring hepatitis A, and offered vaccine.

• For up to date information see>> Hepatitis A
• Full issue>> Annual Summary of Communicable Diseases Reported to the Minnesota Department of Health, 2004