Weather Variability and COVID-19 Transmission: A Review of Recent Research

Abstract

Weather and climate play a significant role in infectious disease transmission, through changes to transmission dynamics, host susceptibility and virus survival in the environment. Exploring the association of weather variables and COVID-19 transmission is vital in understanding the potential for seasonality and future outbreaks and developing early warning systems. Previous research examined the effects of weather on COVID-19, but the findings appeared inconsistent. This review aims to summarize the currently available literature on the association between weather and COVID-19 incidence and provide possible suggestions for developing weather-based early warning system for COVID-19 transmission. Studies eligible for inclusion used ecological methods to evaluate associations between weather (i.e., temperature, humidity, wind speed and rainfall) and COVID-19 transmission. The review showed that temperature was reported as significant in the greatest number of studies, with COVID-19 incidence increasing as temperature decreased and the highest incidence reported in the temperature range of 0–17 °C. Humidity was also significantly associated with COVID-19 incidence, though the reported results were mixed, with studies reporting positive and negative correlation. A significant interaction between humidity and temperature was also reported. Wind speed and rainfall results were not consistent across studies. Weather variables including temperature and humidity can contribute to increased transmission of COVID-19, particularly in winter conditions through increased host susceptibility and viability of the virus. While there is less indication of an association with wind speed and rainfall, these may contribute to behavioral changes that decrease exposure and risk of infection. Understanding the implications of associations with weather variables and seasonal variations for monitoring and control of future outbreaks is essential for early warning systems.

Weather variability and transmissibility of COVID-19: a time series analysis based on effective reproductive number

“…Previous research showed absolute or relative humidity had positive or negative influence on COVID-19 transmission (Guo, Zhang, & Zeng, 2020;McClymont & Hu, 2021;Park, Son, Ryu, Choi, & Ahn, 2019). These studies reported marginal correlations between humidity and COVID-19 cases number.…”

“…However, the role of meteorological effect on the spread of COVID-19 is still controversial (Demongeot, Flet-Berliac, & Seligmann, 2020;Qi et al, 2020;Tosepu et al, 2020). A recent review on 23 studies about weather and COVID-19 showed that temperature and humidity can contribute to increased transmission of COVID-19, particularly in winter conditions which is a conductive environment for virus survival (McClymont & Hu, 2021). For example, a study on the growth of new cases in tropical and temperate regions showed that temperature has a positive association with the number of daily new cases (Chennakesavulu & Reddy, 2020).…”

Overcoming COVID-19 in China despite shortcomings of the public health system: what can we learn?

“…There was some discussion in the beginning whether Wuhan managed to control the pandemic because of the geographical location and the respective climate [ 66 ]. However, while other states located at the same altitude (e.G.…”

“…There is a clear negative correlation between temperature and COVID-19 incidence, but for other parameters (e.g. humidity, wind speed, rain fall) the results are not significant [ 66 ]. It is likely that temperature does not have a direct impact on the transmission of the virus but increases the parameter m and n , i.e., during the cold season people have more and closer contact in rooms.…”

Possible effects of air temperature on COVID‐19 disease severity and transmission rates

“…The majority of currently available studies suggest that outdoor temperature is negatively correlated with COVID-19 transmission rates, although findings are not unanimous. [70][71][72][73][74][75][76] Despite an abundance of studies on this topic, the implications are still unclear as the data are rife with confounding variables. Some confounding variables are behavioral: For instance, during cold weather, people spend more time indoors, which supports more efficient transmission.…”