[IanPBann]

I caught it in September when numbers here in the UK were quite low.

I'm not sure how I caught it. I had left my car into the garage a few days before I showed symptoms and had to get an Uber home, then back to the garage to pick it up, so my strongest suspicion is one of the Uber drivers or previous passengers had it or potentially a mechanic had it and it remained in the car.

The strangest thing is my girlfriend and I had spent the day before I showed symptoms together and she slept over that night but she didn't seem to catch it off me. She even had an antibody test about a month after which was negative suggesting she hadn't already had asymptomatic Covid.

[spfzero]

I think it is possible to be exposed to the virus and never need to build antibodies. Innate immune response, if robust, can fight off (or block) infection quickly enough that the adaptive immune response, never kicks in. Adaptive response takes time, and antibodies don't show up until a few days in, IIRC .