Are morning vaccines more effective?

Pensioners vaccinated before 11am had up to four times the immune response compared to those in the afternoon, new research from the University of Birmingham suggests...

Publishing in Vaccine this week, Dr. Anna Phillips and her team followed 276 patients from 24 GP surgeries in the West Midlands, UK and varied whether they had their flu vaccine in the morning (9-11am) or the afternoon (3-5pm).

Phillips measured the response of antibodies to different strains in the flu vaccine before and after the vaccination and found that two of the three strains responded better to the morning jab.

There were up to four times as many antibodies for one of the strains and an increase of one and a half times for another, whilst the remaining strain showed no difference in antibodies response.

"Obviously we've got to test fully in a larger sample how much this translates into clinical significance but for now this is a free intervention, it's no risk to patients so why not just have your vaccine in the morning?" she told the Naked Scientists.

At the moment though, the researchers have no clear idea why this is the case.

They measured the levels of immune messengers and various hormones, which do vary throughout the day, but none of them were responsible for the observed increase in antibodies.

One theory is that it could be due to fluctuations in the numbers of some different types of immune cells.

The team also weren't able to follow up the patients who showed increased levels of antibodies to see whether this led to an improved resistance to the flu.

But the initial result is still promising and Phillips remains positive that they'll see a similar effect in other vaccines.

"I can't see why we wouldn't be able to apply it to all vaccines," she said. "We'd need to test this properly so it'd be really good to go and test a different type of vaccine such as pneumonia, that'd be a really key one for older people."

Vaccines help your body to produce the specific antibodies it needs to fight off infection, but as we get older, they can become less effective as our bodies produce fewer antibodies in response.

For older patients, this puts them at higher risk of diseases such as flu, which kills up to half a million people every year.