A study could shed light on why there’s a different Covid-19 mortality rate between both sexes
As the number of deaths due to Covid-19 increase all over the world, there is a pattern that repeats all over. The pattern shows that men who are getting sicker and dying as a result of this virus. For example, in New York male deaths account for nearly 70%.
But New York is not alone, since its appearance in Wuhan, China, men have been getting sicker and at a higher pace than women. And that pattern is being repeated from country to country with only small variations.
Scientists are not completely sure why that is but there are some clues.
A preliminary study that tracked viral elimination from patients in Mumbai (India), offered further proof that men are in fact most affected by this novel coronavirus. According to this study, men that face infection by this coronavirus can have a pair of vulnerabilities that can increase the risk of a longer and more severe disease: their own testicles.
The study offered a theoretical explanation for the difference in severity of the disease between men and women that focused on the types of cells coronavirus is mostly attracted to. These cells serve as an entrance for the virus because they have an enzyme that modifies angiotensin 2, which the virus uses to attach itself.
In both men and women these proteins ACE2, or receptors, are in great concentrations in the lungs, the GI tract and the heart. It’s not at all surprising that those tissues are most susceptible to the virus that causes Covid-19. But in addition to the above, testicular tissue also gives off ACE2 receptors in great numbers.
A group of scientists directed by Dr. Aditi Shastri, an oncologist at the Montefiore Medical Center in New York and her mother, microbiologist Jayanthi Shastri from the National School of Medicine in Topiwala, Mumbai, formulated a hypothesis which is only at a preliminary stage: that testicles can harbor Sars-Cov-2 (the name of the virus that causes Covid-19) giving it safe haven from the man’s immune system.
While women give this coronavirus plenty of openings to enter her cells, men’s testicles can give the virus and extra door. Also, since testicles are isolated form the immune system, they can serve as one of the last hiding places for the novel coronavirus.
According to Dr. Aditi Shastri in an interview with the Los Angeles Times, the work must be explored by the professionals who work with cell cultures, animals, and the ever-growing number of patients that have recovered from Covid-19.
Dr. Aditi Shastri directed a New York-based team while her mother, Jayanthi Shastri directed the work in Mumbai. The scientists in India tested hospitalized patients and their family members every two days to see the speed by which the patients eliminated the virus once they were infected.
In 20 women patients the median time of elimination of the virus was four days. In 48 males, the median was 50% longer. A similar pattern emerged with there extensive families sick with Covid-19 whose members took viral tests every two days to see the speed in which they eliminated the virus.
This hypothesis was presented in a preliminary publication published in MedRxiv, a website where researchers share their unfinished work. This is not like a published article in a medical journal, as the work has not yet been peer reviewed.
Still, this hypothesis has some important arguments “below its belt":
First, there is already a number of pathogens that hide somewhere in the body in order to avoid the body’s immune system. For example, the virus that causes Ebola hides in pigment cells inside the human retina, even after the patient has fully recovered.
Second, it’s a biologically plausible explanation for the observed disparity between the sexes in Covid-19 infections. We already know that the coronavirus attaches itself to ACE2 receptors, which there are plenty only in certain types of tissue, including your testicles.
Thirdly, it can help explain a pattern that’s being seen with the Covid-19 pandemic. While the index of confirmed cases is becoming to equalize, the mortality rate is notably higher in men than in women in China, South Korea, Italy, and the United States. In New York 68% of deaths from Covid-19 have been men, while only 32% women.
Nonetheless this hypothesis does not yet have clear evidence that correlates testicles and Covid-19. There are many other factors that could explain the disparity between the sexes. For example, men are more likely to smoke cigarettes than women, and more likely to suffer from high-blood pressure and have coronary disease. All these conditions make men more likely to get gravely ill from this coronavirus.
Dr. Shastri added that if this coronavirus, in fact, is hiding in your testicles, this could mean that the virus can be sexually transmitted and it would definitely be transmitted by semen.
Dr. Kathryn Sandberg from the University of Georgetown who studies the gender differences in immune responses said that we know that women eliminate many kinds of viruses faster than men, in part because they have a stronger immune response. She said that the idea that the virus could find a safe place in the testicles is “speculative”. But it’s important to keep in mind that there is certainly plenty of ACE2 in your testicles, and this could be part of the problem.