I'd go to the christening and skip the Grand Final BBQ. Or skip both. Your son is too young at the moment to expose him to people who could be sick. It will be pass the parcel with the baby and he'll get overtired as well. Not to mention you've got a trip tomorrow and you're still sore.

A friend of mine recently ended up with her 5 month in hospital with a collapsed lung due to a viral infection he picked up from someone. Even at that age, his lungs were too underdeveloped for them to do anything except give him oxygen and hope he pulled through. I'm sorry if that's alarmist, but I'm pretty paranoid about things like that.