Sex, Hormones, Immune Functions, and Susceptibility to Coronavirus Disease 2019 (COVID-19)-Related Morbidity.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the virus that causes coronavirus disease 2019 (COVID-19), uses two primary receptors, type II transmembrane serine protease and angiotensin-converting enzyme-2, for priming and cellular invasion, respectively. Both proteins have been demonstrated to be present in different concentrations in females and males, which may explain a mechanism for the reported higher case-fatality rate in males. Despite the known sex difference in COVID-19 disease mortality, preliminary data suggest there are certain female populations, including pregnant and menopausal women and possibly polycystic ovarian syndrome patients who are more susceptible to COVID-19-related morbidity. This commentary analyzes the interplay between sex differences, hormones, and the immune function in each of these populations with respect to the risk and severity of COVID-19 and proposes biological rationales to explain these differences.