My so called best friend often gets a cold. She works in a school ( I work in a different one) and IMO colds etc are par for the course, especially when you work with very little ones.
The other week I had a cold. She didn't see me till the Sunday when she already had cold symptoms and is claiming she caught the cold from me.
She has made comments such as " I always get a cold a few days after you" or "no-one at my chool had a cold so it couldn't be from there" 
I have tried explaining how the cold virus can be transmitted and incubation periods etc but she doesn't seem to believe any of it. I even tried to explain how the virus can be transmitted via hands such as touching door handles or petrol pumps and not washing hands before eating but she rubbished all that too.
She also believes that paracetamol actually cure colds but that's another story
What can I say or do to show her she isn't catching all her colds from me?
AIBU? It's really starting to annoy me now and would love to know what to say to her.