If we told you that men in the morning had a better response to vaccinations for hepatitis A and influenza, you might think there was some biology bias at work, but that's what a study led by Anna Catriona Phillips of the University of Birmingham found. They assessed the response to a hepatitis A vaccine in young healthy adults and also examined responses to the annual influenza vaccination in older community-based adults.
In the first study, participants consisted of 75 University of Birmingham students who were vaccinated with the hepatitis A vaccine during a morning session (10 am to 12 pm) or early evening session (4 pm to 6 pm). In the second study, 90 older adults attended their medical practice for the annual influenza vaccination and received the vaccination in the morning between 8 am and 11 am or in the afternoon between 1 pm and 4 pm.
Men vaccinated in the morning showed the strongest immune response. Almost twice as many men showed a twofold increase in antibody response when vaccinated in the morning as opposed to the afternoon.
"If we can replicate these findings in a randomized controlled trial, there would be implications for the time of day for vaccinating those at risk," the authors conclude. "Adults could be vaccinated at a specific time of day to increase their protection against the flu."
