紫外线灯消毒对冬季学校乙型流感疫情防控效果分析

Efficacy of ultraviolet light in influenza B prevention and control in schools of Shenzhen in winter

目的评估紫外线灯消毒在冬季学校乙型流感疫情防控中的实际效果,为开展学校乙型流感防控提供参考。方法采用多阶段分层整群抽样方法,现场检测深圳盐田区11所学校98个班级紫外线灯下不同距离的辐照值,通过统计建模,与学生健康监测信息系统报告的班级流感病例数进行相关分析。结果共检测473盏紫外线灯,合格率为53.91%,达到合格辐照值对应灯下有效距离为(1.43±0.54)m,每个班级单位时间总有效辐照体积为(13.65±32.66)m^3。共74个班报告流感599例,罹患率为13.76%,其中58个班报告流感聚集性疫情,占59.18%,疫情持续时间(14.5±25.25)d。Spearman相关分析显示,单位时间紫外线灯有效辐照体积占教室体积比与班级流感罹患率呈负相关(r=-0.32,P=0.00),与流感疫情持续时间的关联无统计学意义(P=0.78)。纳入"不同学校"进行协方差分析显示,班级流感罹患率、流感疫情持续时间与紫外线灯有效辐射照体积占教室体积比的关联均无统计学意义(P值均>0.05)。结论紫外线灯消毒措施未能有效降低2017-2018年冬季深圳盐田区学校各班级乙型流感罹患率及流感疫情持续时间。

Objective To evaluate the efficacy of ultraviolet light in influenza B prevention and control in schools in Yantian District of Shenzhen in winter, and to provide a reference for preventing and controlling influenza B in schools. Methods Multistage stratified cluster sampling was conducted. Ultraviolet irradiance was detected in 98 classes of 11 schools. The irradiance of different distances under each ultraviolet lamp were measured. Correlational analysis was conducted with influenza cases reported by Shenzhen Student Health Surveillance System. Results A total of 473 ultraviolet lamps were detected, the qualified rate was 53.91%. The effective distance from the lamp corresponding power supply to efficient irradiance was(1.43±0.54)m. The total effective irradiance volume per unit time of each class was(13.65±32.66)m^3. Totally 599 influenza cases in 74 classes were reported, with incidence rate of 13.76%. Fifty-eight classes reported influenza clustering, accounting for 59.18%. Average duration of the epidemic was(14.5±25.25)d. Spearman correlation analysis showed that the proportion of irradiance volume per unit time in classroom volume was negatively correlated with class influenza incidence(r=-0.32, P=0.00), but not significant with duration of influenza epidemic(P=0.78). Covariance analysis showed that the incidence of influenza and the duration of influenza epidemic in classes was not significantly correlated with the proportion of irradiance volume per class per unit time in classroom volume(P>0.05). Conclusion Ultraviolet light might not effectively reduce the incidence rate of influenza B and the duration of influenza epidemic in schools in Yantian District of Shenzhen over 2017-2018 winter.