Infections reveal inequality between the sexes

Stark differences between men and women’s immune responses pose medical conundrum. The immune systems of men and women respond very differently to infection — and scientists are taking notice. Research presented last week at a microbiology meeting in Boston, Massachusetts, suggests that the split could influence the design of vaccination programmes and lead to more targeted treatment of illness. Hints that men and women deal with infection differently have been around for some time. In 1992, the World Health Organization hastily withdrew a new measles vaccine after it was linked to a substantial increase in deaths of infant girls in clinical trials in Senegal and Haiti. It is still not clear why boys were unaffected, but the incident was one of the first such examples to catch scientists’ attention. Women might have evolved a particularly fast and strong immune response to protect developing fetuses and newborn babies, says Marcus Altfeld, an immunologist at...