Ultraviolet A Radiation and COVID-19 Deaths in the USA with replication studies in England and Italy

Abstract

<jats:p>Objectives To determine whether UVA exposure might be associated with COVID-19 deaths Design Ecological model and meta-analysis Setting 2,474 counties of the contiguous USA, 6,755 municipalities in Italy, 6,274 areas in England. Data were collected during their Vitamin D winter (monthly mean UVvitd of under 165 KJ/m2) from Jan to April 2020. Participants The at-risk population is the total county population, with measures to incorporate spatial infection into the model. The model is adjusted for: age, ethnicity, socioeconomic deprivation, long term PM2.5, and UV weighted by the vitamin D action spectrum. Main outcome measures We derive UVA measures for each area and estimate their relationship with COVID-19 mortality with a random effect for States, in a multilevel zero-inflated negative binomial model. In the USA and England death certificates had to record COVID-19. In Italy excess deaths in 2020 over expected from 2015-19. Data sources Satellite derived mean daily UVA dataset from Japan Aerospace Exploration Agency. Data on deaths compiled by Center for Disease Control (USA), Office for National Statistics (England) and Italian Institute of Statistics. Results Daily mean UVA (January-April 2020) varied between 450 to 1,000 KJ/m2 across the three countries. Our fully adjusted model showed an inverse correlation between UVA and COVID-19 mortality with a Mortality Risk Ratio (MRR) of 0.73 (0.62 to 0.87)per 100KJ/m2 increase UVA in the USA, 0.81 (0.71 to 0.93) in Italy and 0.51 (0.39 to 0.66) in England. Pooled MRR was 0.68 (0.53 to 0.66). Conclusions Our analysis, replicated in 3 independent national datasets, suggests ambient UVA exposure is associated with lower COVID-19 specific mortality. This effect is independent of vitamin D, as it occurred at irradiances below that likely to induce significant cutaneous vitamin D3 synthesis. Causal interpretations must be made cautiously in observational studies. Nonetheless this study suggests strategies for reduction of COVID-19 mortality</jats:p>

Investigating the Potential for Ultraviolet Light to Modulate Morbidity and Mortality From COVID-19: A Narrative Review and Update

“…Some “beneficial” inverse associations of higher ambient UV levels and lower COVID-19 mortality have been detected in most studies done to-date. We observed a dose-dependent correlation between average ambient UVA levels (from satellite-derived data, measured in January-April 2020) and COVID-19 deaths, in a trio of studies carried out in the USA, United Kingdom and Italy, then pooled to show a reduced mortality risk ratio of 0.68 (95% CI 0.53–0.89) per 100 kJ/m 2 increase in mean daily UV ( 48 ) (preprint). These data were corrected for the vitamin D-weighted solar spectrum (excluding the vitamin D-forming UVB component).…”

“…Combined with the potential for UV light to compromise viral-specific T cell responses, high doses of UV light could increase susceptibility for COVID-19, although it is likely that the timing between when UV and viral exposures occur will be an important determinant. In the observational study of Cherrie et al ( 48 ) (described above), the greater reductions from COVID-19 deaths were linked to increases in UV exposure from lower baseline levels. This effect tailed off as environmental UV light increased, suggesting that there may be an upper limit to the levels of UV light associated with reduced COVID-19 mortality.…”

On the anti-correlation between COVID-19 infection rate and natural UV light in the UK

“…Another study [3] pointed out that UV radiation will not be effective in places with high air pollution, where UV light turns into heat. On the other hand, other studies [4–6] have found that UV light is associated with decreased COVID-19 growth rate. Given the disagreement on the impact of UV light on COVID-19 transmission we take a fresh look at data for the UK.…”

Weather and COVID-19 Deaths During the Stay-at-Home Order in the United States

“… 8 – 18 Transmission rates also appeared lower with higher humidity, 9 , 12 – 17 , 19 – 23 higher ambient U.V. light index 14 , 17 , 24 lower wind speed, higher greenness, 25 and lower precipitation. 9 , 16 , 23 Other studies, however, reported weak or no relationships between weather metrics and transmission rates.…”