Figure 1.

(A) Demographic and genetic data for the COVID-19 cohort.

Age and sex distribution of patients with life-threatening COVID-19. Reproduced, with permission, from [5]. (B) Sex differences in factors that affect infection and immunity in COVID-19. SARS-CoV-2 binds to ACE2 to initiate host cell entry. This activates the viral RNA sensors TLR3/7/8 and RIG-I–MDA-5, which induce secretion of IFNs and other inflammatory cytokines, leading to innate and adaptive immune responses. In each of these steps, sex differences may shape the antiviral immune response. Reproduced, with permission, from [9]. Abbreviations: ACE2, angiotensin-converting enzyme 2; IFN, interferon; IRF, interferon regulatory factor; MDA-5, melanoma differentiation–associated protein 5; NF-kB, nuclear factor kB; RIG-I, retinoic acid–inducible gene 1; SARS-CoV-2, severe acute respiratory syndrome coronavirus 2; TLR, Toll-like receptor.