COVID-19 Infection in the Human Reproductive Tract of Men and Nonpregnant Women

SARS-CoV-2 is an enveloped non-segmented positive-sense RNA virus, classified as a beta coronavirus, responsible for the COVID-19 pandemic. Angiotensin-converting enzyme 2 (ACE2), reported as a SARS-CoV-2 receptor, is expressed in different human tissues (lung, intestine, and kidney) and in the testis, ovaries, uterus, and vagina. This suggests a potential risk to the human reproductive tract in COVID-19 patients. In addition, SARS-CoV-2 RNA has been detected in the blood, urine, facial/anal swabs, semen, and vaginal secretion, suggesting other potential means of transmission. However, little has been reported about SARS-CoV-2 infection in the male and nonpregnant female reproductive tracts, which may provide direct evidence on sexual transmission and fertility problems. Therefore, we focused this narrative review mainly on the distribution of ACE2 and SARS-CoV-2 positivity in the male and nonpregnant female reproductive tracts, providing an overview of the potential threat of COVID-19 to reproductive health and sexual transmission.