湖南省气温对新型冠状病毒肺炎发病数的滞后影响

目的  研究湖南省日均气温对COVID-19日发病数的滞后影响，为疫情的有效防控提供科学依据。方法  本研究对2020年1月21日―2020年3月2日湖南省气象因素和空气质量因素与COVID-19日发病数进行Spearman相关分析和分布滞后非线性模型分析。结果  观察期间，湖南省新型冠状病毒肺炎报告新发病例共1 018例。分布滞后非线性模型结果显示，日均气温与COVID-19日发病数的关系呈非线性，累积发病风险随气温的升高而降低，且发病人群的气温风险最低点为0 ℃。高温对日发病数的影响为短期即时效应，低温对每日发病人数的影响具有滞后性，滞后效应长达12 d，当日均温为-5 ℃，滞后天数为8 d时，相对危险度最高(RR=2.20, 95% CI=1.16~4.19)，且高温(10 ℃)较低温(6 ℃)影响更为显著。结论  气温是影响湖南省COVID-19发病的因素，且有滞后性；高温和低温均可导致发病风险升高，应针对脆弱人群和危重患者加强防护措施从而降低发病风险。

Lag effect of temperature on the incidence of COVID-19 in Hunan Province

  Objective  To explore the lag effect of daily average temperature on the incidence of coronavirus disease 2019 (COVID-19) in Hunan Province and to provide scientific evidences for effective prevention of COVID-19.  Methods  The meteorological factors, the air quality factors and the data conincidence of COVID-19 reported in Hunan Province during January 21, 2020 to March 2, 2020 were collected. Spearman correlation and distributed lag non-linear model analysis were performed.  Results  A total of 1 018 COVID-19 cases were reported in Hunan Province. The distribution lag non-linear model results showed that the influence of daily average temperature on the incidence of COVID-19 presented a nonlinear relationship. The cumulative relative incidence risk of COVID-19 decreased with the increase of daily average temperature, and the lowest temperature risk of the patients was 0 ℃. Both cold temperature and hot temperature increased incidence risk of COVID-19. It was indicated that the hot effects were immediate, however, the cold effects with obvious lag effect persisted up to 12 days. The highest relative risk of COVID-19 incidence was associated with lag 8-day daily average temperature of -5 ℃(RR=2.20, 95% CI=1.16-4.19). The influence of high temperature(10 ℃) was more significant than that of low temperature(6 ℃).  Conclusion  The daily average temperature, especially cold or hot temperature, was an important influencing factor of the incidence of COVID-19 in Hunan Province, which had lag influence on the incidence of COVID-19. We suggested that some related preventive measures should be adopted to protect vulnerable population and severe patients to reduce the incidence risk.