ABSTRACT
Objective@#To understand the situation of varicella prevalence and vaccination of susceptible population in Longhua District，and to provide reference for the varicella immunization program.@*Methods@#A total of 23 706 children from 30 childcare facilities and primary schools in 6 streets were randomly selected throughout the Longhua District. Date on age, grade, recent year and dosage of vaccination, varicella incidence, the overview of vaccination were collected and analyzed.@*Results@#The rate of vaccination in childcare facilities and primary schools was 86.01%, including 55.61% of 1 dose and 30.41% of 2 doses of vaccine. The differences of rate vaccination rate between the childcare facilities and primary schools had statistical significance(χ2=154.95, P<0.05).Rate of no-vaccination,1 dose vaccination and 2 doses vaccination across 6 streets differed significantly(χ2=146.09, 103.93, 127.31, 146.09, P<0.05). There was an increasing positive association between grades and attack rate(χ2=8.65，P<0.05). The differences of attack rate between the childcare facilities and primary schools was of statistical significance(χ2=478.69, P<0.05). The differences of attack rate in street of no vaccination,1 dose vaccination and total attack rate showed statistical significance(χ2=54.49, 74.59, 151.49，P<0.05). There was an increasing linear trend of attack rate of primary school childrenby each year(χ2=24.28，P<0.05). The attack rate increased with time after 1 dose vaccination, immune protection was obtuined for a longer period time after additional doses of vaccine.Negative association was found between grades and protective efficacy rate of varicella. The protective rate and efficacy index of different doses of vaccine in different grades were correlated(r=0.80，0.63，P<0.05). It was most effective after 1 dose vaccination among children in junior grade in kindergarten and 2 dose vaccination in senior grade.@*Conclusion@#After the implementation of vaccination program in Longhua District, the vaccination rate of 2 doses significantly increased, but not for a long time. Varicella vaccine should be included in immunization programme to protect vulnerable populations.