Hygiene doesn't harm immune development

A question we’re being asked quite a lot is whether the extra lengths we’re going to in terms of hygiene to protect us from COVID-19 might cause us immune problems later because we’re living lives that are too clean. This is the basis of what’s dubbed the “hygiene hypothesis”. But a report out this week says that, actually, it’s the environment we’ve created - rather than the way we clean it - that matters, because modern living conditions and building materials select for the wrong sorts of microbes. Microbiologist and author of the report, Graham Rook, spoke to Chris Smith...