Abstract: American Journal of Infection Control 48 (2020) 1042−1044 Contents lists available at ScienceDirect American Journal of Infection Control journal homepage: www.ajicjournal.org Major Article COVID-19 fatalities, latitude, sunlight, and vitamin D Paul B. Whittemore PhD * Pepperdine University, Newport Beach, CA Key Words: Death rates Proximity to the equator UV radiation Insufficient vitamin D Background: Since Vitamin D is known to be vital in regulating the immune system, and sunlight UV radiation exposure on the skin produces Vitamin D and UV intensity is highest nearest the equator, a study was done to examine the correlation between the latitude and COVID-19 fatality rates for countries. Methods: Eighty-eight countries were selected based on their likelihood of providing reliable data. Using death rates/million for each country from the “worldometer” website, a correlation analysis was done between death rates and a country’s latitude. Results: A highly significant, positive correlation was found between lower death rates and a country’s proximity to the equator (Pearson r = 0.40 P < .0001, 2-tailed t test). The R squared of 0.16 means that 16% of the variation in death rates among nations is accounted for by the latitude of the country. Evidence is presented suggesting a direct correlation between sunlight exposure and reduced mortality. Discussion: This study is the first to document a statistically significant correlation between a country’s latitude and its COVID-19 mortality and is consistent with other research regarding latitude, Vitamin D deficiency, and COVID-19 fatalities. Limitations of this study are noted. Conclusions: Further research is needed to confirm the correlation between latitude and COVID-19 fatalities, and to determine the optimum amounts of safe sunlight exposure and/or vitamin D oral supplementation to reduce COVID-19 fatalities in populations that are at high risk for vitamin D deficiency. © 2020 Association for Professionals in Infection Control and Epidemiology, Inc. Published by Elsevier Inc. All rights reserved. As the COVID-19 pandemic spread, death rates reported for over 200 countries and territories on the “worldometer” website appeared to be higher in countries farther from the equator compared with those closer to the equator.1 A striking example of this appeared in the May 11, 2020 data between Ireland and Singapore, whose population size was similar (4.9 million vs 5.3 million, respectively), total number of cases were similar (23,135 vs 23,822, respectively), and number of cases per million of their population was similar (4,685/million vs 4,072/million, respectively). However, the number of deaths in Ireland was 297/million compared with 4/million in Singapore.1 Despite similar numbers of cases, Ireland had 74 times more fatalities than Singapore. By the second week of May 2020, several medical studies appeared describing significant correlations between Vitamin D insufficiency, COVID-19 mortality rates, and the suspected pathophysiology of COVID-19 deaths.2-6 Without adequate Vitamin D levels, the lungs are vulnerable to fatal immune system dysregulation including but not limited to cytokine storms, insufficient protection from epithelial cell apoptosis, and deficient epithelial cell repair.4,6 * Address correspondence to Paul B. Whittemore, PhD, 1001 Dove Street, #145, Newport Beach, CA 92660 E-mail address: paulwhittemore@earthlink.net (P.B. Whittemore). Conflicts of interest: None to..