Faculty of Engineering Sciences, Heidelberg University, Heidelberg, Germany.
Department of Public Health, Environments and Society, London School of Hygiene & Tropical Medicine, London, UK.
Sci Total Environ. 2023 Jan 1;854:158636. doi: 10.1016/j.scitotenv.2022.158636. Epub 2022 Sep 7.
The associations between COVID-19 transmission and meteorological factors are scientifically debated. Several studies have been conducted worldwide, with inconsistent findings. However, often these studies had methodological issues, e.g., did not exclude important confounding factors, or had limited geographic or temporal resolution. Our aim was to quantify associations between temporal variations in COVID-19 incidence and meteorological variables globally.
We analysed data from 455 cities across 20 countries from 3 February to 31 October 2020. We used a time-series analysis that assumes a quasi-Poisson distribution of the cases and incorporates distributed lag non-linear modelling for the exposure associations at the city-level while considering effects of autocorrelation, long-term trends, and day of the week. The confounding by governmental measures was accounted for by incorporating the Oxford Governmental Stringency Index. The effects of daily mean air temperature, relative and absolute humidity, and UV radiation were estimated by applying a meta-regression of local estimates with multi-level random effects for location, country, and climatic zone.
We found that air temperature and absolute humidity influenced the spread of COVID-19 over a lag period of 15 days. Pooling the estimates globally showed that overall low temperatures (7.5 °C compared to 17.0 °C) and low absolute humidity (6.0 g/m compared to 11.0 g/m) were associated with higher COVID-19 incidence (RR temp =1.33 with 95%CI: 1.08; 1.64 and RR AH =1.33 with 95%CI: 1.12; 1.57). RH revealed no significant trend and for UV some evidence of a positive association was found. These results were robust to sensitivity analysis. However, the study results also emphasise the heterogeneity of these associations in different countries.
Globally, our results suggest that comparatively low temperatures and low absolute humidity were associated with increased risks of COVID-19 incidence. However, this study underlines regional heterogeneity of weather-related effects on COVID-19 transmission.
新冠病毒传播与气象因素之间的关联在科学上存在争议。全球范围内已经开展了多项研究，但研究结果并不一致。然而，这些研究往往存在方法学问题，例如，未排除重要的混杂因素，或者地理或时间分辨率有限。我们的目的是量化全球范围内新冠病毒发病率的时间变化与气象变量之间的关联。
我们分析了来自 20 个国家的 455 个城市的数据，时间范围为 2020 年 2 月 3 日至 10 月 31 日。我们使用时间序列分析，假设病例呈拟泊松分布，并在城市层面上结合分布式滞后非线性模型来考虑暴露关联，同时考虑自相关、长期趋势和星期几的影响。通过纳入牛津政府严格程度指数来解释政府措施的混杂作用。通过应用局部估计的荟萃回归，并结合位置、国家和气候带的多层次随机效应，来估计日平均气温、相对湿度和绝对湿度以及紫外线辐射的影响。
我们发现气温和绝对湿度对新冠病毒传播有 15 天的滞后影响。全球范围内的综合估计表明，总体而言，低温（7.5°C 相比 17.0°C）和低绝对湿度（6.0g/m 相比 11.0g/m）与较高的新冠病毒发病率相关（RRtemp=1.33，95%CI：1.08；1.64 和 RR AH =1.33，95%CI：1.12；1.57）。相对湿度没有明显的趋势，而紫外线则有一定的正相关证据。这些结果在敏感性分析中也是稳健的。然而，研究结果也强调了这些关联在不同国家的异质性。
总体而言，我们的结果表明，相对较低的温度和较低的绝对湿度与新冠病毒发病率的增加有关。然而，本研究强调了天气因素对新冠病毒传播的影响存在区域性差异。
