Department of Pathogenic Biology, West China School of Basic Medical Sciences & Forensic Medicine, Sichuan University, Chengdu 610041, China.
Sichuan Center for Disease Control and Prevention, Chengdu 610041, China.
Epidemics. 2022 Dec;41:100650. doi: 10.1016/j.epidem.2022.100650. Epub 2022 Nov 9.
The effects of climatic conditions on the prevalence of individual influenza (sub)types are not well understood in the subtropics. This study aims to evaluate the associations between meteorological factors and seasonal epidemics of A(H3N2), A(H1N1)pdm09, and type B influenza viruses, as well as to estimate the interactions between climatic variables in a subtropical basin region.
The seasonality of influenza (sub)types during 2010-2019 were characterized in Chengdu Plain Economic Zone, a densely populated and highly humid plain area in Sichuan Basin in subtropical Southwest China. Generalized additive models were adopted to assess the independent exposure-response relationship between meteorological variables and influenza prevalence. The interactions of meteorological variables were further estimated using bivariate response surface models and strata models.
Our analyses indicated that the temperature, relative humidity, and absolute humidity have exhibited a major influence on influenza infection in Chengdu Plain Economic Zone. Low temperature was shown to promote the prevalence of A(H1N1)pdm09 and type B in winter-spring days at all levels of relative humidity. High risk of A(H3N2) infections was observed at low temperature or high temperature, and at higher relative humidity. Moreover, absolute humidity decreased or increased influenza (sub)type infections within different ranges.
This study found different nonlinear relationships between meteorological factors and the seasonality of influenza (sub)types, as well as significant interactive effects between climatic variables, contributing to the research on the climate drivers of influenza prevalence in warm-humid basin regions in the subtropics.
在亚热带地区，气候条件对流感（亚型）流行的影响尚不清楚。本研究旨在评估气象因素与 A(H3N2)、A(H1N1)pdm09 和 B 型流感病毒季节性流行之间的关系，并估计亚热带流域地区气候变量之间的相互作用。
在亚热带西南地区四川盆地人口稠密、高度湿润的成都平原经济区，对 2010-2019 年期间流感（亚型）的季节性进行了描述。采用广义加性模型评估气象变量与流感流行之间的独立暴露反应关系。进一步使用双变量响应曲面模型和分层模型来估计气象变量之间的相互作用。
我们的分析表明，温度、相对湿度和绝对湿度对成都平原经济区流感感染有较大影响。低温在所有相对湿度水平下促进了冬季-春季 A(H1N1)pdm09 和 B 型的流行。低温或高温以及相对湿度较高时，A(H3N2)感染的风险较高。此外，绝对湿度在不同范围内会降低或增加流感（亚型）感染。
本研究发现气象因素与流感（亚型）季节性之间存在不同的非线性关系，以及气候变量之间存在显著的交互作用，为温暖湿润流域地区流感流行的气候驱动因素研究提供了依据。
