Gender, Time Affect Vaccine Response

Men, but not women, vaccinated in the morning experience a better peak antibody response to both hepatitis A and influenza, British researchers said.

Study leader Anna Catriona Phillips of the University of Birmingham assessed the response to a hepatitis A vaccine in young healthy adults, and examined responses to the annual influenza vaccination in older community-based adults.

In the first study, 75 University of Birmingham students who were vaccinated with the hepatitis A vaccine during a morning session, 10 a.m. to noon, or early evening session, 4 p.m. to 6 p.m.

In the second study, 90 older adults attended their medical practice for the annual influenza vaccination and received the vaccination between 8 a.m. and 11 a.m. or between 1 p.m. and 4 p.m.

The study, published in the journal Psychophysiology, found almost twice as many men showed a two-fold 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 said in a statement. Adults could be vaccinated at a specific time of day to increase their protection against the flu.