Objective To analyze the epidemiological investigation and treatment of a varicella outbreak in Chaoyang district,Beijing,involving herpes zoster(HZ)cases on campus,and to provide reference for scientific prevention and control of varicella and HZ on campus in the future.Methods An active search for varicella and HZ cases and epidemiological investigation were carried out in the affected middle school.Utilizing descriptive epidemiological method to describe the epidemic characteristics of the outbreak.The attack rates of the groups with and without VarV immunization history were analyzed,and the vaccine effectiveness(VE)of VarV was evaluated.Results A total of 1 case of HZ and 6 cases of varicella occurred in the middle school from October 31 to December 16,2021.The incidence rate of varicella was 0.37％(4/1 083)for first-year students and 0.63％(2/319)for teachers,with no statistical significance(P=0.625).Excluding students with unknown VarV immunization history and previous varicella,among the students on the floor where the varicella cases were located,14.45％(76/526)had a history of 1 dose of immunization and 84.98％(447/526)had a history of 2 doses of immunization.The attack rate in the group with a history of VarV immunization was 0.57％(3/523),and the attack rate in the group without a history of VarV immunization was 33.33％(1/3).The difference in attack rate between the two groups was statistically significant(x2=10.115,P=0.023),and the RR value was 0.017(95％CI:0.002-0.122).The overall VE was 98.29％(95％CI:87.807％-99.757％).The skin samples of 3 varicella cases and 1 HZ case were collected,and the nucleic acid test results were positive.The sequence consistency of whole genome sequencing pairwise alignment was 99.85％-99.99％.Conclusions The 2-dose varicella vaccination program has a good protective effect.Even with a high coverage rate of the chickenpox vaccine,there is still a possibility of varicella outbreaks in schools,but the scale of the outbreak is likely to be smaller.It is important to strengthen the surveillance of HZ cases in the school and increase attention to varicella cases among teachers,ensuring timely isolation and management to prevent the further spread of the epidemic.
维普
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