Evidence of Protective Role of Ultraviolet-B (UVB) Radiation in Reducing COVID-19 Deaths
Forthcoming, Scientific Reports
55 Pages Posted: 1 May 2020 Last revised: 9 Oct 2020
Date Written: April 1, 2020
Background. Prior studies indicate the protective role of Ultraviolet-B (UVB) radiation in
human health, mediated by vitamin D synthesis. In this observational study, we empirically
outline a negative association of UVB radiation as measured by ultraviolet index (UVI) with
the number of COVID-19 deaths.
Methods. We apply a fixed-effect log-linear regression model to a panel dataset of 152
countries over 108 days (n=6524). We use the cumulative number of COVID-19 deaths and
case-fatality rate (CFR) as the main dependent variables and isolate the UVI effect from
potential confounding factors.
Findings. After controlling for time-constant and time-varying factors, we find that a permanent
unit increase in UVI is associated with a 1.2 percentage points decline in daily growth rates of
cumulative COVID-19 deaths [p < 0.01] and a 1.0 percentage points decline in the CFR daily
growth rate [p < 0.05]. These results represent a significant percentage reduction in terms of
daily growth rates of cumulative COVID-19 deaths (-12%) and CFR (-38%).
Interpretation. We find a significant negative association between UVI and COVID-19
deaths, indicating evidence of the protective role of UVB in mitigating COVID-19 deaths. If
confirmed via clinical studies, then the possibility of mitigating COVID-19 deaths via
sensible sunlight exposure or vitamin D intervention would be very attractive.
Note: Funding: This study is not sponsored by any organization.
Conflict of Interest: RKM is a part-time PhD student at Goethe University, Frankfurt. He also is a full-time employee of a multinational chemical company involved in vitamin D business and holds the shares of the company. This study is intended to contribute to the ongoing COVID-19 crisis and is not sponsored by his company. BS also holds shares of the company. All other authors declare no competing interests.
Keywords: COVID-19; Coronavirus; UVB Radiation; UV Index; Ultraviolet; Sunlight; Vitamin D; Vitamin D deficiency; Vitamin D COVID-19; COVID-19 Clinical outcome; Infectious disease; Public health; COVID-19 Clinical Trial; Mortality
JEL Classification: I1,I10, I12, I18, I28, J1, I18
Suggested Citation: Suggested Citation