Duh. Sorry, I do know it is a bacteria. Thats what you get when NAK a baby and emotional toddler make demands while trying to post Lesson to take a step back from the computer when I am needed IRL.
Transmission is most likely during the catarrhal stage, not the coughing stage.
I am not making these points to pick a fight about choosing this vaccines. Pertussis is scary. And some people feel much safer with the vaccine. I am pointing out that there is not good evidence that the vaccine prevents transmission and there is a lot of work being done to try and control pertussis with a vaccine. Perhaps a newer vaccine will have more success.
Oh, there's definitely room for improvement with the vaccine; no doubt about that. Pertussis seems like a bacteria that can't be outsmarted by man. For me (and it was a long journey to come to this point), its the best we've got and is better than no protection at all. We had pertussis go through our house several years ago, and while it was fairly mild for us, its still worth avoiding... if for no other reason than it is such a long time to be sick.