Impact of climate change on SARS-CoV-2 epidemic in China

Epidemics involving the human-to-human transmission of coronaviruses have occurred in regions with subtropical monsoon climates in the Northern Hemisphere during the winter and spring [9, 10]. Global warming and extreme weather affect disease outbreaks and trans- mission [10]. Suitable weather conditions facilitate outbreaks and epidemics. SARS and MERS coronavirus outbreaks in the Coronaviridae family first occurred in regions of subtropical monsoon climates, e.g., SARS in Guangdong Province, China, in 2002 [11]. The Yellow Fever [12], dengue [13], and Zika virus [14] have caused several outbreaks, mainly in the tropical regions of South America, Central America, and Africa, and also in tropical countries in Asia, where the risk varies depending on precipitation, temperature, and rapid urbanization [15, 16]. Recent studies have shown that low temperatures promote the spread of the SARS-CoV-2 infection. Wang et al. [17] suggested that transmission peaks at 8.72˚C, based on counting the number of confirmed cases and temperatures worldwide. Sajadi et al. [18] discovered that the transmission of outbreaks was the highest at temperatures between 4˚C and 11˚C and relative humidity levels between 47% and 79%. Elevated temperatures inhibit the spread of SARS-- CoV-2 [19, 20]. For example, Shaman et al. [21] discovered that an increase in autumn mortal- ity due to SARS-CoV-2 in the UK in 2020 was associated with seasonality. However, Briz- Redon and Serrano-Aroca [22] reported controversial findings regarding the effect of temper-

ature, possibly reflecting spatial heterogeneity in the relationship between temperature and SARS-CoV-2 transmission. Additionally, the effects of humidity [10, 19, 23], wind speed [20, 24], and atmospheric pressure [19, 25] have been investigated. UV radiation was shown to inhibit the spread of an epidemic. Most of these studies were conducted on a global scale. However, the Chinese region has unique climatic and regional features, and epidemic preven- tion and control should be established based on regional characteristics. Therefore, a regional analysis based on previous studies is needed. According to the principle of epidemiological transmission, physical isolation is the most direct and effective method for preventing and controlling SARS-CoV-2 [26–28]. Most coun- tries have implemented a series of non-drug interventions [29] to effectively control the spread of SARS-CoV-2 [30, 31]. Carleton et al. [25] reported that the effect of climate is less significant than that of physical isolation. However, policies and regulations impose direct effects only in the short term. By contrast, weather factors can have indirect long-term effects. The SARS-CoV-2 spread worldwide, which significantly affected the economies and lives of residents in various countries. Different policy strategies have been developed in multiple regions in response to this crisis; however, these strategies are limited. For this study, China is selected as the study area and the provincial administrative region as the smallest organiza-

tional unit. The specific humidity (H), 2-m temperature (T), total precipitation (TP), ultravio- let (UV) radiation, wind speed (WS), and surface pressure (SP) are selected as weather factors to analyze the spatio-temporal distribution characteristics. The effects of weather factors on SARS-CoV-2 should be investigated to facilitate efforts toward long-term epidemic prevention. Material and methods Study area China has a complex and diverse climate spanning tropical, subtropical, warm temperate, mid- dle temperate, and cold temperate zones from south to north. The eastern region features a wide range of monsoon climates; the continental monsoon prevails in the winter, which is cold and dry; and the marine monsoon prevails in the summer, which is hot, humid, and rainy. The high altitude and large area of the Tibetan Plateau results in a distinct alpine cli- mate. The northwestern region is located inland and is not affected by the marine monsoon; PLOS ONE Impact of climate change on SARS-CoV-2 epidemic in China PLOS ONE | https://doi.org/10.1371/journal.pone.0285179 July 27, 2023 2 / 21