An outbreak of hepatitis A in a French day-care center and efforts to combat it

An outbreak of hepatitis A in a French day-care center was identified during a survey of risk factors for such events in a sample of 210 centers. In the period between 29 March and 9 July 1994, 17 cases were diagnosed in the center (anti-HAV IgM serum antibody) including 11 children aged 2-3 (attack rate = 55.5% of class), 2 staff members, 3 parents and 1 educator-parent (secondary attack rate = 27.6%). The source case was probably a classmate of Case 1's older brother, who was diagnosed earlier in the spring. Intensive hygiene measures and the organisational features of the clinic limited all transmission except by direct physical contact with infected children, Vaccination of staff was begun too late to be effective; gamma-globulin prophylaxis might have been administered but was not. This is the first documented outbreak of the disease in a French center.