Selective estrogen receptor modulators in COVID-19. a possible therapeutic option

Male and female genders exhibit significant differences in the outcome of infective diseases caused by several viral pathogens. Along with behavioral or social factors which can affect the exposure to infection and the availability of therapies, it is widely accepted that genetic and physiological factors can markedly influence sex-related differences in immune responses. In particular, receptors for gonadal hormones are expressed in many immune cell types and, consistently, sex-related differences in immune function are likely to be strongly influenced by circulating sex steroid hormones (Klein and Huber, 2010). Concerning coronaviruses, epidemiological data from SARS epidemic (severe acute respiratory syndrome caused by SARS-CoV in 2002–2003) and MERS epidemic (Middle East respiratory syndrome, caused by MERS-CoV in 2012–2013) showed evident sex-dependent differences in disease outcome (Karlberg et al., 2004). Notably, such a sex-dependent difference is presently observed in the new SARS pandemic, broken out in 2019 and caused by SARS-CoV-2 (COVID-19). In particular, susceptibility to SARS-CoV-2 infection is almost similar in both genders, but higher severity and mortality are observed in male patients (Wenham et al., 2020).