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.

Background Different studies support the inverse correlation between solar exposure and Coronavirus SARS-CoV-2 infection. In Spain, the global incidence of COVID-19 is different depending on latitude from Canary Islands to North Spain which could be related with different meteorological conditions as temperature, humidity, and ultraviolet index (UVI). The objective of the present work was to analyze the association between UVI and other relevant environmental factor such as temperature or humidity with the incidence and severity/mortality of COVID19 in different latitudes in Spain. Methods An observational prospective study was used to analyzed number of new cases, hospitalizations, patients in critical units as well as mortality and annual variations related to UVI, temperature, and humidity in 5 different provinces of Spain from January 2020 to February 2021. Results Statistically significant inverse correlation (Spearman coefficients) was observed between UVI and temperature and the annual evolution and COVID-19 incidental cases in all and almost all latitudes respectively. Conclusion Higher ultraviolet radiation levels and mean temperature could contribute in reducing COVID-19 incidence, hospitalizations and mortality.