Across many diseases, taking medication at specific times of day may make the therapy more effective
Jyoti Madhusoodanan, The Scientist
For three consecutive winters, starting in 2011, researchers at the University of Birmingham asked healthy men and women over the age of 65 to come in to clinics across the western Midlands in the U.K. for a seasonal influenza vaccination at specific times of day—either between 9 and 11 a.m., or between 3 and 5 p.m. Blood drawn a month later revealed that participants, who totaled nearly 300 over the three years, had higher levels of anti-flu antibodies if they’d received their vaccinations in the morning.1 The results suggested that daily rhythms of people’s bodies tweaked the vaccine’s effectiveness. Lead author Anna Phillips Whittaker had suspected as much, after observing similar trends in her studies on behavioral factors such as exercise that affect vaccination responses, and in the wake of a growing body of literature suggesting that a little timing can go a long way when it comes to health.
Many hormones and immune signals are produced rhythmically in 24-hour cycles. Cortisol, for example, which is known to suppress inflammation and regulate certain T cell–mediated immune responses, peaks early in the morning and ebbs as the day progresses. Other facets of the immune system undergo similar cycles that could underlie the differences in antibody responses Phillips observed among people receiving the flu vaccine. Much more work is required to nail down the immune mechanisms responsible for such variation and exploit them appropriately, she says. But timing flu vaccine delivery would be straightforward to implement. “It’s such a simple, low-risk intervention that’s free to do, and could have massive implications for vulnerable populations.”