Flu shots given a morning boost

Administering a flu vaccine in the morning could provide better protection than giving the same jab in the afternoon. The new research from the University of Birmingham builds on the idea that our immune system listens to our body clock and responds differently at different times of day.

In this study, 276 adults aged over 65 were vaccinated against three strains of influenza in either a morning or afternoon surgery. Each person had their antibody levels measured immediately before the jab and again one month later. For two of the three strains, those vaccinated in the morning had significantly more antibodies after a month than those in the afternoon cohort.

Flu jabs are regularly given to those people most at risk from influenza, many of whom are over 65. Older people generally experience a decline in immunity, reducing their ability to produce an adequate antibody response following vaccination. A boost from the immune system’s natural rhythm could help combat this and lead to better protection against flu. Moreover, this potential benefit comes at no extra cost.

However it is not clear why the effect was seen in only two of the three strains, and some have cast doubt on the findings of what was a relatively small trial. Ben Neuman, a virologist at Reading University, said “The idea that a six-hour delay in the start of the month-long, mostly random process of making antibodies could make any meaningful difference to the outcome doesn’t make much sense to me.” He questions whether there was truly no difference between the morning and afternoon groups. The Birmingham team is now looking to investigate the effect further in a large scale study, considering those with conditions such as liver and kidney disease that otherwise impair their immunity.

Image credit: Alex Treadway on Flickr