Morning flu shot might be more effective than afternoon

(Reuters Health) – You’re better off getting your flu shot in the morning than in the afternoon, researchers from England say.

“This is a free (course of action) that could seriously boost older adults’ vaccination response with no adverse effects,” Dr. Anna C. Phillips from University of Birmingham told Reuters Health by email.

Vaccines work by getting the immune system to produce infection-fighting antibodies that swing into action upon exposure to the actual disease.

Because a person’s immune response varies through the course of the day, some researchers have suggested that vaccines might work better if they’re given at some times of the day rather than at other times.

Phillips’s team randomly assigned 276 older adults to receive an influenza vaccine in the morning (9-11 AM) or in the afternoon (3-5 PM).

One month later, they analyzed blood samples from each person to measure antibodies against the flu virus.

Antibody levels went up in both groups, but the increases were significantly higher for those who got vaccinations in the morning instead of in the afternoon, the authors reported in the journal Vaccine.

Men and women both showed better responses after the morning vaccination.