Researchers at Montefiore Health System and Albert Einstein College of Medicine, in collaboration with the Kasturba Hospital for Infectious Diseases in Mumbai, India, may have solved a mystery surrounding the novel coronavirus pandemic. The scientists reveal why men infected by the virus generally show more severe symptoms and are more likely than women to die from COVID-19.

This never seen before information showed that men clear the virus from their bodies slower than women due to a potential male-only "reservoir" for coronavirus. "COVID-19 studies worldwide have consistently shown a higher incidence and greater severity of the disease in men compared with women," says Aditi Shastri, M.D., assistant professor of medicine at Einstein, a clinical oncologist at the Montefiore Einstein Center for Cancer Care, and lead author of the Montefiore-Einstein study. "Our collaborative study found that men have more difficulty clearing coronavirus following infection, which could explain their more serious problems with COVID-19 disease."

According to MedRxiv, a website created by Cold Spring Harbor Laboratory to make research quickly available to the scientific community before undergoing the usual peer-review process, the analysis involved 68 people with symptoms of COVID-19 who were examined at India's Kasturba Hospital for Infectious Diseases, in Mumbai. After the researchers proceeded to swab 48 men and 20 women to confirm an active infection, the individuals were re-tested with serial swabs until the tests turned negative, indicating the time taken to clear the coronavirus. According to the researchers, females cleared the virus significantly earlier than men: "a median of four days for women vs. six days for men."

The viral-clearance analysis also revealed that in three Mumbai families were men and women had tested positive for coronavirus infection, the females cleared the coronavirus earlier than male members of the same family.

Seeking a molecular explanation and questioning why do men have trouble shaking off their infections? The researchers involved focused on how coronavirus infection occurs. As revealed by the study, to infect cells, "coronaviruses must first latch onto well-known proteins, called ACE2 receptors, that sprout like tiny antennae from the surfaces of cells. Cell types expressing copious levels of ACE2 on their surfaces would theoretically be most susceptible to infection."

Consulting three independent databases with information on ACE2 expression in different tissues, the researchers saw that the testes, "along with the lungs and kidneys, were among the areas of the body with the highest ACE2 expression. By contrast, ACE2 could not be detected in tissue of the ovaries, the female equivalent of the testes."

Dr. Shastri stresses that the novel coronavirus' ability to infect and multiply in testicular tissue needs to be confirmed, but says it wouldn't surprise her. According to the information, a recent study from China "compared the levels and ratios of sex hormones in male COVID-19 patients vs. healthy men of the same age" indicating that the COVID-19 patients had experienced impaired testicular function. According to the case, this might be a piece of evidence that confirms that the testes may be significantly affected when men develop COVID-19. Such a COVID-19 complication could have important medical and public health implications, she notes and deserves to be investigated by clinical trials.

Besides Jayanthi Shastri, M.D., the analysis was conducted by senior authors Amit Verma, M.B.B.S., professor of medicine and of developmental & molecular biology at Einstein and director of hematologic malignancies at Montefiore; and Ulrich Steidl, M.D., Ph.D., professor of cell biology and of medicine and the Diane and Arthur B. Belfer Faculty Scholar in Cancer Research at Einstein, and associate chair for translational research in oncology at Montefiore.