This means that they don't actually target the bacteria itself (you can look this up).
As a result, it is not possible - even if you accept that the vaccine works perfectly - for the vaccine to prevent transmission of the disease.
Those who are fully vaccinated are just as likely - no more no less - to harbor the bacteria and spread it as the unvaccinated.
Even immunologists and epidemiologists accept this but governments and vaccine fascists routinely ignore it because it doesn't suit their narrative.
The correct conclusion is that there is no point trying to reason with pro-vaxers. You may as well try and explain calculus to a cocker spaniel.
They only understand two things - fear and authority.
Your arguments need to be targeted at that.
You will learn how to do that in my how to guide on debating pro-vaxers.
PM me if you want a copy - and you want a copy.
But just for starters tell them this:
"You take your child to a doctor office where they will be surrounded by dozens of sick people and turn them into a biological weapon? How irresponsible are you?
I do everything I can to avoid infecting my children, including not taking them to a doctor office all the time, and then people like you come along and try and infect their own and other people's children through their selfish actions."
^ You can make the above a little more tactful if you like but the substance should remain the same. Explain to them that if they were truly scared of germs, they would never visit a clinic or hospital.
The "a" in DTaP stands for "acellular" which means not the whole cell. That is, it doesn't contain the actual bacteria itself but just components of it.
Previously, they used to give the DTwP (whole cell pertussis) which they then discontinued because they were struggling to cover up the damage. I suppose in theory that vaccine could have prevented the bacteria itself, but the new one can't.
Here is the WHO reiterating what I am saying - so you can use this.
"To address the adverse reactions observed with the whole-cell vaccines, aP vaccines were developed that contain purified components of B. pertussis such as inactivated pertussis toxin either alone or in combination with other B. pertussis components such as filamentous haemagglutinin, fimbrial antigens and pertactin."
there is limited value in getting technical with pro-vaxers - casting pearls before swine.
They don't understand the "science" and they don't want to. They just want their hands held by someone in a white coat and being told that they are doing the right thing. They then regurgitate the word "science" over and over because that helps them feel smarter.
You need to shatter their delusions about the infallibility of the wise men and women in white coats and you need to shatter their fear of germs.