I would think you'd be okay although I do hope you did more than wash your hands when you got home - after all, you did say you forgot to LIFT the seat. And I believe you might want to thoroughly clean the inside of the car you traveled in.
Hello~Well, they should be OK, just keep watch on how you all are feeling, and take some extra Vitamin D, C and zinc, this will possibly help any infection that you may have gotten.