How to boost your immune system to avoid colds and coronavirus

You're washing your hands 10 times a day and have stopped touching your face. What else can you do to improve your health and avoid bugs?

It's been a long, wet winter. Everybody has got colds, and now we are braced for a coronavirus epidemic. Boosting our immune system has rarely felt more urgent, but, beyond eating more tangerines and hoping for the best, what else can we do?

Sheena Cruickshank, a professor of immunology at the University of Manchester, has a "shocking cold" when we speak at a safe distance, over the phone. To know how to take care of your immune system, she says, first you need to understand the weapons in your armoury - a cheeringly impressive collection, it turns out.