Most vaccines have side-effects and COVID vaccines are no different. The public are being reassured that if they experience a sore arm where the needle went in, or tiredness, a headache, fever or nausea, these are merely signs that the immune system is working as it should. This has left some people wondering: if that’s the immune system doing what it’s supposed to do, does a lack of side-effects mean my immune system hasn’t been primed to protect me?