There's a large glass jar sitting on my desk, gradually filling up with my hair. It has been coming out in alarming clumps for weeks and whenever I use a brush or pull my fingers across my scalp, a good 30 or so more strands come away. My hairdresser estimates I’ve shed a good quarter of my hair in this short period. My GP told me that hair loss is increasingly common around three months after contracting Covid. Having had the virus myself at the end of last year, that fits. Apparently, the shock of serious illness on the body — it can happen after major surgery or high fevers too — can interrupt your hair’s natural cycle of growth and renewal.