Varicella outbreak among vaccinated children--Nebraska, 2004

On November 19, 2004, a school nurse notified the Nebraska Health and Human Services System (NHHSS) of a varicella outbreak in an elementary school (grades kindergarten through 7). In collaboration with local health department officials and CDC, NHHSS initiated a retrospective cohort study to determine the magnitude of the outbreak, assess vaccine coverage and effectiveness, and compare disease severity among vaccinated and unvaccinated students. This report summarizes the investigation and considers the suitability of school settings for case-based surveillance. The findings highlighted the importance of improving varicella vaccination coverage and implementing varicella vaccination school-entry requirements.