Light O'Clock (Season 4)

Episode 2 – The best time for a vaccine? Circadian rhythms and immunity

Host: Carolina Guidolin | Guest: Cathy A. Wyse

DOI: 10.17617/f585-ws61 | License: CC-BY

Is there a best time for a vaccine? In this episode of Light O'Clock, we speak with Dr Cathy A. Wyse about whether the time of day when we receive a vaccine can influence how we respond to it.

We first discuss how circadian rhythms shape the immune system, how vaccines work, and the difference between vaccine response (e.g., antibody levels) and vaccine effectiveness (i.e., protection against infection or disease). We then discuss why the current evidence remains mixed and how factors such as chronotype, sleep, age, sex, prior immunity, and vaccine type may influence results.

Paper reference: https://doi.org/10.1177/07487304241232447

The key message: the immune system is rhythmic, so timing could matter -- but the evidence is not yet strong enough to recommend one specific time of day for vaccination. For now, the most important advice remains: get vaccinated when you can.