Correlation between UV Index, Temperature and Humidity with Respect to Incidence and Severity of COVID 19 in Spain

Abstract

Background: Various studies support the inverse correlation between solar exposure and Coronavirus SARS-CoV-2 infection. In Spain, from the Canary Islands to the northern part of the country, the global incidence of COVID-19 is different depending on latitude, which could be related to different meteorological conditions such as temperature, humidity, and ultraviolet index (UVI). The objective of the present work was to analyze the association between UVI, other relevant environmental factors such as temperature and humidity, and the incidence, severity, and mortality of COVID-19 at different latitudes in Spain. Methods: An observational prospective study was conducted, recording the numbers of new cases, hospitalizations, patients in critical units, mortality rates, and annual variations related to UVI, temperature, and humidity in five different provinces of Spain from January 2020 to February 2021. Results: Statistically significant inverse correlations (Spearman coefficients) were observed between UVI, temperature, annual changes, and the incidence of COVID-19 cases at almost all latitudes. Conclusion: Higher ultraviolet radiation levels and mean temperatures could contribute to reducing COVID-19 incidence, hospitalizations, and mortality.

A mixture of mobility and meteorological data provides a high correlation with COVID-19 growth in an infection-naive population: a study for Spanish provinces

“…A prominent role has also been attributed to UV radiation, which has been shown to decrease both COVID-19 growth rate ( 19 ) and associated deaths ( 20 , 21 ). For the specific case of Spain, a similar negative (but small) correlation has been found between temperature and UV index and COVID-19 incidence and severity ( 16 , 22 – 24 ), although, for the first months of the epidemics, no consistent evidence was found regarding the existence of a relationship between the accumulated number of COVID-19 cases and temperature values at the province level ( 25 ). Studies of the combined effect of seasonal environmental factors and human mobility ( 26 ), show that UV-index, together with mobility changes in Grocery & Pharmacy, Transit Station, and Workplaces displayed the best performances in predicting R t .…”

The influence of meteorological factors on COVID-19 spread in Italy during the first and second wave

“…We found that relative humidity had little association with COVID-19 spread or severity, whereas increasing solar UV radiation above a threshold of 40 kJ/m 2 had a small beneficial influence. UV light has been shown in a number of laboratory studies to decrease SARS-CoV2- viability ( Park et al, 2022 ; Schuit et al, 2022 ; Su et al, 2022 ), and there is some epidemiologic evidence suggesting an effect in reducing coronavirus transmission among animals and humans ( Carleton et al, 2021 ; Isaia et al, 2021 ; Perez-Gilaberte et al, 2023 ; Sehra et al, 2020 ; Thornton et al, 2022 ), with evidence of a possible threshold ( Nottmeyer et al, 2022 ). The lack of association between outdoor relative humidity and COVID-19 endpoints does not preclude a role for indoor humidity, which could affect airborne infectious disease susceptibility ( Aganovic et al, 2022 ; Wolkoff et al, 2021 ).…”

Influence of Seasonality and Public-Health Interventions on the COVID-19 Pandemic in Northern Europe

“…Other research has shown that solar radiation decreases the transmission of SARS-CoV-2 [115], which has obvious seasonal implications since sunlight is at a maximum during summer months. Recent research has also indicated that higher levels of UV light and mean temperatures may contribute to a reduction in the transmission of COVID-19 as well as a reduction in its incidence, hospitalisations and mortality [116,117].…”