Welcome to What’s Up Docs?, the podcast where doctors and identical twins Chris and Xand van Tulleken cut through the confusion around every aspect of our health and wellbeing.

What defines a well-functioning immune system, and why are some people seemingly "immune" to everything while others catch every cold? In this episode, Chris and Xand dive into the complex mechanics of immunology. They tackle the controversial trend of "immune boosting" and discuss the delicate balance between under-active and over-active responses.

To help unpick this, they're joined by Professor Dan Davis, Head of Life Sciences and Professor of Immunology at Imperial College London and author of Self-Defence - a myth-busting guide to immune health.

If you want to get in touch, you can email us at whatsupdocs@bbc.co.uk or WhatsApp us on 08000 665 123.

Presenters: Drs Chris and Xand van Tulleken Guest: Prof Daniel Davis Producer: Faye Lyons-White Executive Producer: Rami Tzabar Editor: Jo Rowntree Assistant Producer: Maia Miller-Lewis Researcher: Mili Ostojic Tech Lead: Reuben Huxtable Visual Producer: Leon Gower Digital Lead: Richard Berry Composer: Phoebe McFarlane Sound Design: Melvin Rickarby

At the BBC: Assistant Commissioner: Greg Smith Commissioning Editor: Rhian Roberts

A Loftus Media production for BBC Radio 4

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