In this scientific review, the critical role that selenium plays in supporting healthy immunity is examined. First, an overview of the immune system is presented, including evidence of a diminished effectiveness of immune functioning in elderly persons attributable to the process of immunosenescence. Next, the impact of selenium on immune function is described, preparing a path for examining selenium’s role in specific settings, such as influenza vaccine responsiveness in the elderly, HIV infection, and control of tuberculosis.
After considering these potential context-specific benefits of selenium, the relationship between selenium and COVID-19 disease is explored, integrating data linking selenium status with reported COVID-19 outcomes, data describing the severe disruption of selenium homeostasis by COVID-19, and data from the screening of selenium-containing compounds for potential activity against the SARS-CoV-2 virus that causes COVID-19.
By exposing readers to key research results in the fields of nutrition and immunology, this review intends to foster a deeper understanding of the dynamic aspects of immunity that impact health outcomes, particularly the age-related changes in immune function that favor increased vulnerability to infectious disease and drive chronic inflammation. It is concluded that, based upon available evidence, establishing and maintaining adequate selenium levels should be considered an important part of multimodal strategies designed to support overall immune health and promote antiviral resistance.