[Hepatitis A outbreak in a day care center and household transmission]

An outbreak of hepatitis A occurred in a day care center in Madrid between October 2002 and February 2003 and spread to the children's families.

We performed a descriptive study of this outbreak and of the control measures adopted.

The outbreak affected 23 people: eight children aged 1-3 years (attack rate= 8.7 %), two staff members (attack rate=10.5 %), and 13 household contacts. Of the 23 cases, 17 were confirmed by serology and eight patients were hospitalized. The control measures were: (i) increasing general hygiene measures in the home and school and, in particular, those concerning diaper changing by staff, and (ii) vaccination of all pupils aged more than one year (92 children), staff members (16 adults) and family contacts of affected individuals. After vaccination, the epidemic curve showed intrafamilial transmission exclusively. Cases among familial contacts affected adults in contact with asymptomatic children.

Vaccination was effective in controlling the epidemic outbreak within the day care center. However, when outbreaks occur, vaccination should be prescribed to close contacts of all the children, whether symptomatic or not, especially parents and siblings. The recommendation that day care center workers undergo vaccination on taking up their posts should be put into practice, since vaccination is not systematically performed. General vaccination would be the most effective measure for preventing outbreaks in educational centers.