Luodan Suo1, Juan Li1, Dan Zhao1, Fan Yang1, Weixiang Liu1, Jiang Wu1, Xinghuo Pang1, Ying Deng1, Li Lu2. 1. Institute for Immunization and Prevetion, Beijing Center for Disease Prevention and Control, Beijing 100013, China. 2. Institute for Immunization and Prevetion, Beijing Center for Disease Prevention and Control, Beijing 100013, China; Email: lulibj@sina.com.
Abstract
OBJECTIVE: To evaluate the effect of outbreaks control in school settings after a 2 dose varicella vaccine immunization strategy implemented in Beijing. METHODS: Epidemiological data of varicella outbreaks in school and kindergarten settings, which were reported by all 16 districts (county) during 2007-2013 according to the technical management norms of Beijing, was collected. The first dose and second dose varicella vaccine coverage rate of eligible children after the 2 dose varicella vaccine immunization strategy implementation were estimated through BJIIMS. Based on above we analyzed the changes of outbreak quantity, case quantity and the distribution characteristics between the pre-adjustment era (2007-2011 years) and late adjustment era (2013) of the 2 dose immunization strategy. RESULTS: In pre-adjustment era (2007-2011 years), an average of 74 (95% CI: 60-89) outbreaks was reported and 964 (95% CI: 812-1 116) cases were involved per year. In late adjustment era (2013): Outbreaks (35) declined 52.7%, involved cases (371) declined 61.5%; Outbreaks epidemic duration shortened from 22 days of pre-adjustment era to 18 days; Outbreaks involved 10-24 cases declined 64.7% (from 34 to 12); Outbreaks involved ≥ 25 cases declined 71.4% (from 7 to 2); Outbreaks of different school type as well as different regions without exception declined dramatically. Cumulative one-dose vaccine coverage in children of 2-6 yr of age was 89.6% (812 859/907 579), and cumulative second-dose vaccine coverage in children of 4-7 yr of age was 44.3% (289 764/647 732). CONCLUSION: Implementation of a 2 dose varicella vaccine immunization strategy effectively controlled outbreaks in school and kindergarten settings.
OBJECTIVE: To evaluate the effect of outbreaks control in school settings after a 2 dose varicella vaccine immunization strategy implemented in Beijing. METHODS: Epidemiological data of varicella outbreaks in school and kindergarten settings, which were reported by all 16 districts (county) during 2007-2013 according to the technical management norms of Beijing, was collected. The first dose and second dose varicella vaccine coverage rate of eligible children after the 2 dose varicella vaccine immunization strategy implementation were estimated through BJIIMS. Based on above we analyzed the changes of outbreak quantity, case quantity and the distribution characteristics between the pre-adjustment era (2007-2011 years) and late adjustment era (2013) of the 2 dose immunization strategy. RESULTS: In pre-adjustment era (2007-2011 years), an average of 74 (95% CI: 60-89) outbreaks was reported and 964 (95% CI: 812-1 116) cases were involved per year. In late adjustment era (2013): Outbreaks (35) declined 52.7%, involved cases (371) declined 61.5%; Outbreaks epidemic duration shortened from 22 days of pre-adjustment era to 18 days; Outbreaks involved 10-24 cases declined 64.7% (from 34 to 12); Outbreaks involved ≥ 25 cases declined 71.4% (from 7 to 2); Outbreaks of different school type as well as different regions without exception declined dramatically. Cumulative one-dose vaccine coverage in children of 2-6 yr of age was 89.6% (812 859/907 579), and cumulative second-dose vaccine coverage in children of 4-7 yr of age was 44.3% (289 764/647 732). CONCLUSION: Implementation of a 2 dose varicella vaccine immunization strategy effectively controlled outbreaks in school and kindergarten settings.