Study: Immunity boosted by vaccinating men and women at different times

A University of Birmingham scientist's study shows that giving flu vaccinations to men in the morning and women in the afternoon may boost their immunity against disease.

Anna Phillips, a reader in behavioral medicine at the university, and her colleagues found that vaccinations appear to be more effective with men when given in the morning. Women appear to have an immune boost in the afternoon, though it is a smaller effect, Today reports.

"The effect was biggest for men," Phillips said, according to Today. "It wasn't statistically significant in women but seemed to be heading in the right direction."

In the elderly, scheduling men and women for vaccinations at different times of the day could help to overcome the weakening of the immune system that comes with older age. The researchers said that such a scheduling change could save millions of dollars each year by reducing how many people have to go to the hospital for influenza.

"The flu vaccine is not the most effective vaccine and scientists are always trying to find ways to make it more effective in older people," Phillips said, according to Today. "What we are doing is free and there are no side effects. The cost savings could be immense."

The researchers said that the changes in sex hormones such as testosterone may be responsible for the change in vaccination response throughout the day. Men usually have higher levels of testosterone in the morning, according to the Daily Telegraph.