The Flu Virus May Affect Men Worse Than Women, Study Says

According to recent research, women may have a biological advantage over men when flu season rolls around. The study, conducted by a team from Johns Hopkins University, shows that estrogen is an effective shield against flu viral replication.

Studies have shown estrogen to have antiviral effects on HIV, Ebola, and hepatitis in the past, so the team was inspired to investigate if the same is true with influenza. To test their hunch, the researchers sampled nasal cells (the primary target of the flu virus) from both male and female participants. When the female cell cultures were exposed to estradiol, the primary form of the hormone, along with the flu virus, the replication of the virus was reduced significantly. (Generally speaking, the more virus in the body, the more severe the symptoms.)

This was also the case when cells were introduced to bisphenol A and selective estrogen receptor modules (SERM), two compounds that are used as estrogen replacements in hormone therapy. The same hormones seemed to have no effect on male cultures exposed to the virus. The mechanisms responsible for this virus-fighting behavior are the estrogen's receptors, the protein structures responsible for binding to molecules and promoting cell response.

While there have been previous studies published that display the hormone's anitviral properties, this was the first to identify the receptors as their source, says study co-author Sabra Klein. Klein sees potential for therapeutic estrogens as a means of combating the flu. The full findings are reported in American Journal of Physiology—Lung Cellular and Molecular Physiology.