Canadian Journal of Medicine

Abstract

In the early stages of the COVID-19 pandemic, many researchers have investigated non
pharmaceutical interventions for restricting the transmission of severe acute respiratory
syndrome coronavirus 2 (SARS-CoV-2), including sunlight. Regarding the lack of effective
medicines for SARS-CoV-2, the scientific community works to evaluate the effects of physical
features of sunlight such as electromagnetic radiation and thermal energy on viral strains.
Sunlight gained a considerable amount of attention, including an infamous mention in the
White House. Since then, little has become known about further research on the effect of
sunlight on SARS-CoV-2. Existing evidence focuses on germicidal wavelengths of the
Ultraviolet (UV) and the stimulation of vitamin D production. UV radiation types B and C
have a high germicidal capacity but are blocked by the atmosphere due to their harmful effect
on living species. UV radiation type A, which reaches the surface of the earth, has a quite
lower germicidal potential. The contribution of vitamin D in the immune response against
COVID-19 is yet to be discussed. With the third spike of the pandemic affecting more and
more countries worldwide, understanding the effect of sunlight on COVID-19 can help public
health officials to design their action plans. At the same time, shedding light on this matter
will contribute to debunking popular myths circulating since the onset of the pandemic and
draw a clear line between health literacy and misinformation.