WVU professor: Men more likely to have COVID-19 complications
Trending
MORGANTOWN -- Being a man doesn't make someone more likely to be infected with the virus that causes COVID-19, but it might make him more likely to have severe complications or die from it, according to a teacher at West Virginia University.
According to Jennifer Franko, a teaching assistant professor in the School of Medicine who studies sex differences in immune responses, many factors contribute to sex-linked immunological differences, including variations in sex hormones and genetics.
"In general, men tend to be more susceptible to infection than women. While this difference may or may not be specific to coronaviruses, similar trends were seen in previous coronavirus outbreaks, including Severe Acute Respiratory Syndrome (SARS) in 2003 and Middle East Respiratory Syndrome (MERS) in 2012," Franko said. "In both of these instances, higher mortality rates were reported in males versus females. It's the same situation that we're seeing now with SARS-CoV-2."
A less robust immune response in males may result in slower viral clearance and poorer outcomes, she said. Such differences in male versus female immune responses may be the result of hormonal or genetic factors, Franko said.
"For example, in females, estrogen and progesterone are typically thought to stimulate the immune system and may provide a higher level of protection against infection," she said. "In males, testosterone may suppress such a response."
From a genetics standpoint, many immune-related genes are encoded on the X chromosome, Franko said. Females have two copies of the X chromosome. Males have only one.
"In order to balance the dosage of X-linked genes between males and females, one female X chromosome is typically inactivated," Franko said. "Interestingly, we are now beginning to realize that not all of those X-chromosome-linked genes are inactive all the time. In some instances, these genes escape inactivation, resulting in a double dosage effect and higher levels of gene expression in females. If these are immune-related genes, they may correlate with stronger immune responses. This may be an additional reason why females respond to infection with more robust responses."
Scientists also are interested in determining if the strong-male bias is the result of male patients' possessing more underlying conditions that may amplify their risk, such as hypertension or heart disease, Franko said.
"We also don't know if differences in ACE-2 receptor expression, the receptor required for viral entry, may contribute to differences in viral load between males and females," Franko said.