Many clinical studies have shown that men and women differ in their responses to several viral vaccines. A recent one demonstrated that women produce as many antibodies in response to a half dose of the seasonal flu vaccine as men make in response to a full dose. Other studies have revealed similar sex differences in response to vaccines for yellow fever virus, measles, mumps and rubella, hepatitis A and B viruses and herpes simplex virus.Whether vaccines work differently in males than in females is not known.

Clearly, more research on sex-dependent immune responses is needed.In planning for the swine flu, however, public health authorities ignored the evidence that vaccines affect women more strongly than men. To determine the proper dose of H1N1 vaccine, the National Institutes of Health set up studies involving 600 children, from babies to teenagers ” but neglected to investigate whether males and females should get the same dose.

Although our public health authorities remain confident they will eventually have enough vaccine for all Americans who want it, there almost certainly won't be enough for all the vulnerable populations in poorer countries. Only a handful of countries have plants to manufacture influenza vaccine, and the world's wealthiest countries have locked up most of what these plants can produce with signed purchasing contracts. We could make much more ” and potentially save millions of lives ” if we stopped giving women larger doses than they need.

Source: National Institutes of Health