So I learned at school that after a cold virus your body documents that bug so it can never be let in again. How come since just before Christmas I've had the same symptoms 3 times at least now. Exact sore throat which leads to chest infection then head cold & no energy. Don't tell me it's different strains of the same thing & theres millions of different types!? For a month it's been a struggle to do anything productive training wise, just scraping through work. I wouldn't mind but I eat loads of fruit & veg. My colleague Dave blames the migrant workers for bringing in their viral infections. Is this scientifically true or is he just another racist bigot?