Epidemiological analysis on public health emergencies of varicella outbreak and break-through cases

Objective To analyze the epidemiological characteristics of varicella outbreaks and break-through cases in Beijing and provide evidence for varicella prevention and control. Methods Descriptive epidemiology method was used to analyze the data of varicella outbreaks and break-through cases in 2007. Results Among 11 varicella outbreaks reported, most occurred in primary schools (90.9%). The outbreaks were mainly reported in April and Autumn when a new school term started and the first grade students were affected mostly, accounting for 55.6%. As the grade became higher, the case number decreased. The break-through cases with vaccination history accounted for 46.7% (85.5% of them with vaccination history for3 years). Conclusion Primary schools are the priority places for varecilla outbreak prevention and control, Varceilla vaccination may be considered among the first grade students and when outbreak occur the vaccination should be expanded to those with vaccination history for3 years. The further study on varceilla vaccination schedule and on follow up of vaccination effects should be conducted.