Common colds may prime the immune system against Covid, scientists believe, after finding that some people never develop an infection despite repeated exposure to the virus. Researchers at University College London (UCL) have discovered that some people have natural protection against Covid and seem to fight off an infection using pre-existing memory T-cells. https://www.telegraph.co.uk/news/2021/07/02/common-colds-could-prime-immune-system-fight-covid/