[Varicella outbreak in a work center for psychologically handicapped adults]

An outbreak of varicella is described in a training and work center for psychologically handicapped adults with a high susceptibility to the disease.

Descriptive and case-control study. A questionnaire self-complimented by parents and staff of the center was used. A serologic study in order to determine antibodies againts varicella was carried out for people without varicella vaccination or disease history.

Four cases of varicella occurred among 56 students of the center and none among the staff (12 people). 51.8% of students had not history of varicella versus 8.3% of staff (p = 0.009). A recommendation of vaccination against varicella was made for people without history of varicella, and 52.2% were vaccinated. After vaccination, no new cases occurred. In the serological study (11 students and 1 staff), 5 students were sero-negative. In the case-control study, risk of suffering varicella was lower for students with history of varicella, those vaccinated against varicella and those attending less commonly the center.

The outbreak occurred in a high susceptible population, and it is suggested that it is a previously unidentified group of risk. Serological studies of varicella with vaccination of susceptible individuals in these populations may be indicated.