Fig. 1

Summary of age- and sex-related changes in the immune system in relation to COVID-19. Inflammation increases with age in both sexes with age, albeit at higher rates in men. Severe COVID-19 cases have been associated with increased inflammation markers in blood and lung. The efficacy of anti-inflammatory drugs are in trials for COVID-19 patients. B cell numbers decline with age specifically in men. Severe cases of COVID-19 have been associated with reduced B cell numbers. Convalescent plasma transfer is being investigated as a potential therapy for COVID-19 patients. T cell functions decline with age, including declining naïve T cell numbers as well as reduced ability to mount strong responses to immune threats. Declines in T cell numbers have been observed in severe COVID-19 patients. Anti-viral drugs can be useful to boost immune cell responses. These observations might also be useful in assessing disease risk in healthy individuals by studying their immune status. For example, individuals who have less B/T cells, more inflammation or more monoclonal hematopoiesis, might be more prone to devastating health consequences of COVID-19