On the Environmental Determinants of COVID‐19 Seasonality. (31st May 2021)

• Record Type: Journal Article
• Authors: Choi, Yeon‐Woo; Tuel, Alexandre; Eltahir, Elfatih A. B.
• Is Part Of: GeoHealth. Volume 5:Number 6(2021)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2021-05-31
• Subjects: air drying capacity -- COVID‐19 -- environmental determinants -- humidity -- seasonality -- ultraviolet radiation; Environmental health -- Periodicals; Electronic journals; Periodicals; 616.98
• DOI: 10.1029/2021GH000413
• Languages: English
• ISSNs: 2471-1403

Abstract

Abstract: Viral respiratory diseases (VRDs), such as influenza and COVID‐19, are thought to spread faster during winter than during summer. It has been previously argued that cold and dry conditions are more conducive to the transmission of VRDs than warm and humid climates, although this relationship appears restricted to temperate regions and the causal relationship is not well understood. The severe acute respiratory syndrome coronavirus 2 causing COVID‐19 has emerged as a serious global public health problem after the first COVID‐19 reports in Wuhan, China, in late 2019. It is still unclear whether this novel respiratory disease will ultimately prove to be a seasonal endemic disease. Here, we suggest that air drying capacity (ADC; an atmospheric state variable that controls the fate/evolution of the virus‐laden droplets) and ultraviolet radiation (UV) are probable environmental determinants in shaping the transmission of COVID‐19 at the seasonal time scale. These variables, unlike temperature and humidity, provide a physically based framework consistent with the apparent seasonal variability in COVID‐19 and prevalent across a broad range of climates (e.g., Germany and India). Since this disease is known to be influenced by the compounding effect of social, biological, and environmental determinants, this study does not claim that these environmental determinants exclusively shape the seasonality of COVID‐19. However, we argue that ADC and UV play a significant role in COVID‐19 dynamics at the seasonal scale. These findings could help guide the development of a sound adaptation strategy against the pandemic over the coming seasons. Plain Language Summary: There is growing scientific interest in the potential seasonality of COVID‐19 and its links to climate variables. This study aims to determine whether four environmental variables, namely, temperature, humidity, air drying capacity (ADC), and ultraviolet radiation (UV), are probable environmental determinants for the observed seasonal dynamics of COVID‐19 prevalence, based on extensive country‐level data spanning the first year of the pandemic. Although the influence of socio‐economic factors may be dominant, we here suggest that ADC and UV are key environmental determinants of COVID‐19 and can potentially affect the transmission and seasonality of the disease across a wide range of climates. Key Points: The seasonality of COVID‐19 appears to follow seasonality of some environmental variables Seasonality of air drying capacity and ultraviolet radiation consistently matches the seasonality of COVID‐19 across climatic zones Seasonality of air humidity and temperature matches the seasonality of COVID‐19 in temperate climates but not in tropical monsoon climates