Outbreak of hepatitis A in a day care center in Finland.

An outbreak of hepatitis A occurred in a Helsinki day care center attended by 12 children less than 3 years of age. After return of one of the children from Israel, several cases of hepatitis A appeared. Altogether 9 persons, 3 children and 6 adults, developed hepatitis A. The diagnosis was based on measurement of hepatitis A IgM antibodies in serum. Instructions for hygiene and administration of prophylactic gammaglobulin to the personnel and children of the day care center, and to their family members, prevented further spread of the infection. The important role of small infants for spread of hepatitis A is emphasized.