An interesting question which will require additional research is whether vitamin D may play a role in COVID-19. Vitamin D is known to be essential to immune function. Some initial research suggests that vitamin D may reduce COVID-19 severity by suppressing the cytokine storm in COVID-19 patients. Vitamin D deficiency is more common among persons with naturally dark skin. The pigment (melanin) in dark skin doesn’t absorb as much UV radiation, which stimulates natural skin production of vitamin D. This may contribute to an explanation for why African-American and Latinos in the US are more likely to become infected with SARS-CoV2 and experience more severe COVID-19, including being more likely to die from the disease.
A recent study of 14,000 members of an Israeli HMO who were tested for SARS-CoV2 infection from February 1st to April 30th, 2020, and who had at least one previous blood test for plasma vitamin D levels found that low plasma vitamin D levels were associated with an increased likelihood of COVID-19 infection and of hospitalization due to COVID-19.
Undoubtedly more research will continue to shed light (excuse the pun) on this topic.
Preliminary data from California on COVID-19 cases and deaths through May 20, 2020 suggest racial/ethnic disparities in adults diagnosed and dying from the disease caused by the novel coronavirus, SARS-CoV2. While there were substantial amounts of missing data (30% of cases and 2% of deaths were missing information on race/ethnicity) and data are dependent on testing to identify cases, two patterns have emerged. First, adults of Latino and Native Hawaiian/Pacific Islander race/ethnicity are disproportionately more likely to be infected with SARS-CoV2 relative to the proportion of the California population that they make up. Adults of African-American/Black race/ethnicity made up a greater proportion of deaths from COVID-19 relative to their proportion of the California population. The demographic data do not tell us why these patterns may exist but some hypotheses have been put forth. Cases, which indicate infection with COVID-19, may be associated with socioeconomic factors, such as, employment in essential occupations, being less able to work from home or less able or compliant with social distancing. Deaths, which indicate more severe disease once infected, may be reflective of less access to health services, more prevalent comorbidities, or vitamin D deficiency (vitamin D is essential to immune function). More research is needed to examine these potential racial/ethnic disparities.