Estudio de un brote de varicela en un pueblo del Uruguay

Abstract

A varicella outbreak occurred in a Uruguayan village that introduced the varicella vaccine in 1999 with currently high vaccination rates. Aim: To investigate the cause of the outbreak, vaccine effectiveness, and to describe the measures adopted. Material and Methods: Cases that occurred in the kindergarten and schools in the village were investigated. Vaccination cards were examined, history of chickenpox and clinical characteristic of the current episode were obtained and the outcome of the measures were evaluated. An estimate was made of the vaccine's effectiveness. Results: A total of 37 cases of varicella were reported, 14 occurring in previously vaccinated children, in a l total population of 313 children. The global effectiveness of the vaccine was 80%, and 100% for severe cases. A shift of cases towards older ages was demonstrated; vaccinated children had a trend of less fever and lower number of lesions. Immunization of healthy unvaccinated children, mainly adolescents stopped the outbreak. Comments: The vaccine proved to be highly effectivene. In an outbreak situation immunization policies should consider "catch up" vaccination in non-immunized adolescents without a previous history of varicella.