2021年荆州市一起水痘聚集性调查及疫苗保护效果分析

An investigation on the aggregation of varicella and analysis of vaccine protection effect in Jingzhou City in 2021

目的调查一起中学水痘聚集性疫情的发生原因,观察水痘疫苗在疫情中的保护效果。方法2021-02对荆州市某中学水痘聚集性疫情所在学校制定病例定义,开展病例搜索和个案调查,采用描述性流行病学方法描述病例特征;统计病例所在的班级患儿水痘疫苗接种信息进行疫苗保护效果分析;应用R软件进行统计分析,检验水准α=0.05。结果本次疫情共搜索到水痘病例10例。10例病例集中在八年级的同一个班级(年龄均为14岁),班级罹患率为19.61%(10/51)。首发病例首发症状为腰腹部皮疹,无发热;洗澡时由家长发现,症状被发现前正常到校上课。首发病例发病时间为2020-12-30,发病高峰出现在2021-01-13/14,末例病例发病时间为2021-01-15,疫情持续17 d。座位分布显示,距离首发病例所在的小组越近的小组发病率罹患率越高(χ^(2)_(趋势)=5.13,P=0.02)。男性(4/26)、女性(6/25)罹患率差异无统计学意义。病例所在班级内未接种水痘疫苗者、接种1剂次水痘疫苗者和接种2剂次水痘疫苗者罹患率分别为30.00%(3/10)、29.00%(7/24)和0.00%(0/6)。接种疫苗者末次接种水痘疫苗距疫情发生间隔为8~12年。结论此次疫情为水痘聚集性疫情;传播主要是由首发病例潜伏期或发病后继续在校上课引起。接种水痘疫苗8~12年后,1剂次保护效果较差,接种2剂次水痘疫苗保护效果较好。

Objective Investigate the cause of an outbreak of chickenpox in a middle school,and observe the protective effect of chickenpox vaccine in the epidemic.Methods In February 2021,a case definition was formulated for the school where the chickenpox epidemic of a middle school in Jingzhou City was located,case search and case investigation were carried out,and the descriptive epidemiological method was used to describe the characteristics of the case;the class where the case was located was counted on the children with chickenpox vaccination information for vaccination Analysis of protection effect;application of R software for statistical analysis and inspection level was 0.05.Results A total of 10 cases of varicella were found in this epidemic.The 10 cases were concentrated in the same class(all 14 years old)in the eighth grade,and the class attack rate was 19.61%(10/51).The first symptom of the first case was a rash on the waist and abdomen,without fever;it was discovered by the parents when taking a bath,and he went to school normally before the symptoms were discovered.The onset time of the first case was 2020-12-30,the peak onset occurred on January 13/14,2021,the onset time of the last case was January 15,2021,and the epidemic lasted for 17 days.The seat distribution showed that the group closer to the group of the first case had a higher attack rate(χ^(2)trend=5.13,P=0.02).There was no statistically significant difference in attack rates between males(4/26)and females(6/25).The prevalence rates of those who were not vaccinated with varicella vaccine,those who received 1 dose of varicella vaccine,and those who received 2 doses of varicella vaccine were 30%(3/10),29%(7/24)and 0%(0/6).The interval between the last vaccination of varicella vaccine and the outbreak of the vaccinated person is 8-12 years.Conclusions This outbreak is a cluster of chickenpox;the spread is mainly caused by the incubation period of the first case or continuing to attend school after the onset of the disease.Eight to 12 years after vaccination with varicella vaccine,the protective effect of one dose is poor,and the protective effect of two doses of varicella vaccine is better.