Containment of a community-wide hepatitis A outbreak using hepatitis A vaccine.

This report describes the use of hepatitis A vaccine to contain a community-wide hepatitis outbreak. Hepatitis A virus (HAV), an RNA virus in the piconavirus family with an incubation period of 15 to 45 days, causes an acute systemic illness that may include anorexia, nausea, vomiting, fatigue, headache, malaise, arthralgias, myaglias, photophobia, pharyngitis, cough, coryza, low grade fever, dark urine, clay-colored stools, and jaundice. Cyclical community outbreaks of HAV have historically occurred every 5 to 7 years in Northern Plains Indian communities. The index case for an outbreak on the Lower Brule Sioux Reservation was a 9-year-old male child living in a farming community adjacent to the reservation, who became ill in mid-October 1995. Subsequently, a total of 21 cases of hepatitis A were identified from October 1995 to the end of February 1996. Eight of the 21 cases were relatives of one extended Lower Brule family. All affected were Native Americans with the exception of one, a 39-year-old female who was a babysitter for some of this family cluster of eight cases. To contain the outbreak, family members and household contacts of active cases were immune globulin; no serologic testing was done. In addition, 336 (approximately 80 percent) Lower Brule children between the ages of 2 and 12 received hepatitis A vaccine in mid-November, also without serologic testing. The authors conclude that the vaccination, as well as the gamma globulin (administered to household contacts of active cases) in concert with the usual hygiene and health education measures, seemed to effectively arrest the epidemic.