Sex and gender differences in COVID-19: More to be learned!☆

The COVID-19 pandemic has affected millions of patients across the globe. Multiple studies, national and international governmental data have shown important sex and gender differences in the incidence and outcomes of patients with COVID-19. These differences are not only attributed to the differences in age and comorbid conditions but likely a combination of factors, including hormonal differences, immune response, inflammatory markers and behavioral attitudes, among others. In this review, we discuss the studies addressing sex- and gender-specific differences in COVID-19 infections with a focus on the potential pathophysiological mechanisms of these differences.