Objective To analyze the changes in varicella incidence,outbreak and vaccination in Daying County before and after the implementation of the Plan for the Prevention and Control of Varicella in Primary and Secondary School Childcare Institutions (Trial) (hereinafter referred to as the Plan),and to evaluate the effect of two-dose inoculation of varicella vaccine. Methods The surveillance data of varicella cases in Daying County reported in the China Disease Prevention and Control Information System from 2015 to 2022,the relevant data of field epidemiological investigation and disposal of epidemic situation,and the data of varicella vaccination in the Sichuan Immunization Program Management Information System were collected to conduct descriptive epidemiological analysis. Results After the implementation of the Plan in 2019,the total dose,the first dose and the second dose increased by 73.82%,10.96% and 190.03%,respectively.From 2015 to 2022,a total of 1 443 cases of varicella were reported in Daying County,with an annual average reported incidence rate of 45.12/100 000.After the implementation of the Plan,the annual average incidence rate decreased by 62.45% (χ²=15.915,P<0.001).The incidence of varicella decreased by 77.20% in the age group of 1-14 years,of which the incidence rate of varicella in the 5-9 year old group decreased the most,88.99%,and the incidence of varicella increased by 91.83% in the age group of 15-24 years.The total incidence rate of varicella in outbreaks decreased from 1.35% to 0.55%,the number of patients per outbreak decreased from 9.50 to 7.00,the duration of each outbreak decreased from 33.00 to 23.50 days,and the number of generations per outbreak decreased from 1.57 to 1.12. Conclusion The two-dose varicella vaccination program is effective in controlling the occurrence and outbreak of varicella,and it is necessary to continue to implement the two-dose varicella vaccination strategy.