Journal of the Pediatric Infectious Diseases Society, Sep 25;8(4):334-341
The author discusses the connection of the Pertussis vaccine, linked epitope suppression, and how it is similar to something called the “original antigenic sin” in influenza. Basically, once someone is vaccinated, when they are exposed again to the illness that may have several variants, their immunity is imprinted on the one(s) they are vaccinated for, so that their immunity to any others will be minimal.
QUOTE: “Because of linked-epitope suppression, all children who were primed by DTaP vaccines will be more susceptible to pertussis throughout their lifetimes, and there is no easy way to decrease this increased lifetime susceptibility.”
NOTE: And yes — they may be contagious to new babies every time. So if you have a new baby, try not to let anybody around if they have a “cold.”
More info about the Pertussis vaccine and epitope suppression (less than 3 minutes):