Flu vaccine more effective for women than men: Study
WASHINGTON (AFP) - The flu vaccine is generally less effective for men than for women, scientists said in a study on Monday, tracing the effect to higher levels of testosterone that curb the immune response.
It has long been known that men are more vulnerable than women to bacterial, viral and parasitic infections, but scientists have never been able to clearly explain why.
It was also known that men don't respond as strongly as women to vaccines against yellow fever, measles and hepatitis, said the authors of the study, which appears in this week's Proceedings of the American Academy of Sciences.
The new research, using samples from 34 men and 53 women, suggested that the cause could be traced to testosterone: only men with higher levels of the sex hormone demonstrated the lower antibody response to the flu vaccine.