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

Foshan, Guangdong Province, in November 2002, which were very similar in terms of the out- break seasons. Previous studies [29] demonstrated that natural factors, particularly meteoro- logical conditions such as temperature, precipitation, and radiation intensity, change the occurrence and spread of infectious diseases by affecting the pathogens, hosts, and transmis- sion environments. Extreme weather events such as high temperatures, droughts, and floods pose direct risks to human health and indirectly affect the epidemic intensity and scope of infectious diseases [37]. The Chinese region includes six climatic zones: tropical, subtropical, warm temperate, mid- dle temperate, cold temperate, and plateau climatic zones (as shown in S7 Fig). China has a distinctly monsoonal climate, and the seasonal distribution of precipitation varies widely, with the rainy season occurring from April to September in the south and July to August in the north, whereas the winters are relatively dry. Drought may affect the spread of viral infections by damaging the ecological environment. The adverse effect of precipitation on water quality and health during drought periods has been suggested to be higher than that of temperature [38]; additionally, drought can increase water pollution, causing increased pollution concen- trations in river runoffs, deteriorating water quality, and affecting human health [39]. High temperatures and droughts can cause atmospheric pollution. Historically, many cases of drought-induced ecological damage has resulted in epidemic outbreaks [37]. In the analysis of

the spatial distribution characteristics of the SARS-CoV-2 epidemic, the infection rate was higher in provinces located in warm temperate, subtropical, and tropical zones, which is con- sistent with the findings of many previous studies [40]. Not only for SARS-CoV-2, but also for most infectious diseases, the weather characteristics of temperate and tropical regions are more likely to be favored by the virus. The distribution characteristics coincided with those of the Hu Line. From an ecogeographic perspective, the Hu Line segregates the arid zone from the humid zone. The recently discovered 400 mm isoprecipitation line coincides with the Hu Line and revealed a high correlation between weather and population density [36]. Effect of urbanization on SARS-CoV-2. Population density has been shown to be an essential factor that determines the incidence of some infectious diseases, with a high incidence associated with high population density [41]. According to the fifth Chinese census in 2000, the eastern side of the Hu Line comprised approximately 94% of the population in China, Fig 9. Effects of various weather factors on SARS-CoV-2. Notes: GR is the growth rate of SARS-CoV-2, H is specific humidity, T is 2-m temperature, WS is wind speed, UV is ultraviolet, SP is surface pressure, and TP is total precipitation. https://doi.org/10.1371/journal.pone.0285179.g009 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 15 / 21