Testosterone May Undermine Flu Shot's Effectiveness
High levels of the hormone cause fewer antibodies to be produced, researchers say
"There isn't a difference in the amount of protection from flu. Women just don't need as much vaccine," Mensch said.
In this study, which involved 53 women and 34 men, researchers found that, in general, women had a stronger antibody response to the vaccine. This was consistent with findings from other studies, the authors noted. However, men with low testosterone levels had an antibody response similar to women.
Furman's team also noticed that the activity of certain genes in men, but not women, was associated with a weakened antibody response to the flu vaccine.
When they looked at male testosterone levels in relation to gene activity, they saw increased activation of the Module 52 genes in men with high testosterone levels. This resulted in reduced antibody production for the flu, the researchers concluded.
But in women, activation levels of Module 52 genes had no significant effect on flu antibody levels, the study authors noted.
Some Module 52 genes are known to be related to the immune system. The connections between these genes and testosterone might be a target for further study and drug development, Furman said.
One unanswered question is what evolutionary purpose is served by having testosterone connected to the immune system, Furman said.
It's possible that an overly robust immune response might be more dangerous than the disease itself. For example, women with their robust immune responses are twice as likely as men to die from infections that invade the blood system, Furman explained.
So maybe a somewhat less robust immune system can be lifesaving for men, he suggested.