There's still a lot of misunderstanding about HMG response to #COVID_19uk. I'm no epidemiologist, but I *am* an expert at explaining biological ideas to people, so here is an explainer thread of the situation. Corrections / questions welcome. 1/n First up - vaccines and immunity.

A vaccine is a medicine which helps you become immune to a particular disease without making you ill. Your immune system responds to the weakened version of the disease (the vaccine), thus building immunity to the real disease. 2/n