Summary of COVID-19 sunlight studies
1. Pereira et al., Cardiopulmonary and hematological effects of infrared LED photobiomodulation in the treatment of SARS-COV2
30 patient sunlight RCT: 32% shorter hospitalization (p=0.02) and 38% faster recovery (p=0.0006).RCT 30 hospitalized COVID-19 patients investigating the effectiveness of photobiomodulation (PBM) using a vest with near-infrared LEDs (simulating part of the sunlight spectrum). The treatment group showed shorter hospitalization, significant improvement in cardiopulmonary function, and improvements in leukocyte, neutrophil, and lymphocyte counts post-treatment. The treatment group had higher pneumonia severity at baseline. For more discussion see [youtube.com].
Dec 2022, J. Photochemistry and Photobiology B: Biology, https://www.sciencedirect.com/science/article/pii/S1011134422002342, https://c19p.org/pereira2
sunlight study: 45% lower mortality (p<0.0001).
Ecological study of 129 geographical regions worldwide showing lower COVID-19 mortality with higher ambient Ultraviolet (UV) Index, sunlight duration, and temperature. Authors analyzed daily data from January 2020 to January 2023 utilizing panel Poisson Distributed Lag Models with 7-to-21-day exposure windows. Results demonstrated that a one-standard-deviation increase in the UV Index had the strongest negative association with mortality, followed by sunlight duration and ambient temperature. The study controlled for dynamic confounders like PM2.5 and relative humidity, which were found to be statistically insignificant, suggesting mortality reductions are driven by solar radiative intensity rather than simply clear or dry weather. However, the study relies on aggregate ecological data and deliberately excludes explicit seasonal controls to avoid over-adjustment bias, therefore the results cannot establish causality and may be confounded by human behavioral shifts, such as increased..
Mar 2026, COVID, https://www.mdpi.com/2673-8112/6/4/56, https://c19p.org/razi
3. Kalichuran et al., Vitamin D status and COVID-19 severity
100 patient sunlight study: 58% fewer symptomatic cases (p=0.004).Prospective study of 100 COVID-19 patients in South Africa, 50 with COVID-19 pneumonia and 50 asymptomatic, showing higher risk of symptomatic COVID-19 with lower exposure to sunlight, and with vitamin D deficiency. Sunlight exposure may be correlated with physical activity and may have additional benefits independent of vitamin D [sciencedirect.com].
Apr 2022, Southern African J. Infectious Diseases, https://sajid.co.za/index.php/sajid/article/view/359, https://c19p.org/kalichuransun
4. Cherrie et al., Ultraviolet A radiation and COVID-19 deaths in the USA with replication studies in England and Italy
sunlight study: 32% lower mortality (p=0.004).Analysis of UVA exposure and COVID-19 mortality in the USA, England, and Italy, showing increased UVA exposure associated with lower mortality.
Apr 2021, British J. Dermatology, https://onlinelibrary.wiley.com/doi/10.1111/bjd.20093, https://c19p.org/cherrie
5. Jabbar et al., Vitamin D Serum Levels and Its Association With COVID 19 Infection In Babylon Governorate, Iraq
240 patient sunlight study: 63% fewer cases (p=0.0002).Analysis of 120 COVID-19 and 120 control patients in Iraq, showing lower risk of cases with regular sunlight exposure (3 times/week).
Dec 2021, Natural Volatiles & Essential Oils, https://www.nveo.org/index.php/journal/article/view/1046, https://c19p.org/jabbarsun
19,535 patient sunlight study: 23% fewer cases (p=0.0001).
Analysis of 39,915 patients with 1,768 COVID+ cases based on surveys in the Nurses' Health Study II, showing higher UVA/UVB exposure associated with lower risk of COVID-19 cases.
Dec 2021, The American J. Clinical Nutrition, https://academic.oup.com/ajcn/advance-article/doi/10.1093/ajcn/nqab389/6448988, https://c19p.org/ma2sun