Some immunological differences such as the lower production of pro-inflammatory interleukin-6 (IL-6) after viral infection in women (24), the potentially protective role of estrogen and progesterone (25), and the higher expression of angiotensin-converting enzyme-2 (ACE2) and transmembrane protease serine 2 (TMPRSS2) receptors in men and women (24) could explain the higher occurrence of post-COVID-19 signs and symptoms. The gene discussed is ACE2; the disease is viral infectious disease.