New York, Dec 25 (IANS): When it comes to immunity, women seem to leave men -- especially those with high testosterone levels -- way behind.

If we are to believe a new study, women have a stronger immune response than men when given the flu vaccine shot.

“Now we have literature to say that women have better responses in general to infectious diseases, including flu,” Mark Davis, a professor of microbiology and immunology at the
Stanford School of Medicine, was quoted as saying.

“Vaccinated women are better protected against catching the flu than vaccinated men,” he added.

To reach this conclusion, researchers examined the inflammatory responses of 53 women and 34 men post-flu vaccination.

They found that men had a weaker response, or less inflammation in their bodies, than women after receiving the vaccine, and the response was weakest among some of the men who had the highest testosterone levels.

High testosterone levels suppresses inflammation, the study noted.

“It’s also possible there is a genetic component to people’s flu responses. We found the flu vaccine activated certain genes, and this activation predicted who would have the weakest flu shot response,” the researchers added.

They said that an evolutionary reason may explain why men would benefit from suppressed immune systems. In evolutionary terms, men may have experienced more trauma than women, so they may have benefitted from a less-active immune system.

“There might be a way to disconnect the testosterone suppression to, say, getting better immunity,” Davis said.

Researchers also want to know why women have much higher rates of certain immune diseases, and why during pregnancy, those diseases may go into remission.

The findings of the study were published in the latest edition of the journal Proceedings of the National Academy of Sciences.