There are a lot of moving parts in our immune system and scientist still haven't figured out how the system works. Vaccination is a hit or miss when it comes to providing a life time immunization from a disease, that is why we need booster shoots.
Here is an article by Suzan Humphrey, many people don't like the good doctor but I have learned a lot from her.
In natural immunity, the body reacts very strongly to ACT, but because of original antigenic sin and the absence of ACT in the vaccine, the vaccinated are not programmed to respond to it at all. Vaccines do not boost antibody to this toxin, because as of yet, nobody has figured how to put that antigen into the vaccine. The naturally convalesced have more than 17 times the amount of antibody to ACT than DTaP recipients and more than 9 times than DTP vaccinated, as measured after pertussis infection.552 There is only a miniscule level of ACT antibody in the vaccinated, which is the result of the immune system’s paralyzed effort to mount a response after programming by the vaccine.
Original Antigenic Sin Committed by Vaccination
https://vaccinechoicecanada.com/resources/books-periodicals/original-antigenic-sin-committed-by-vaccination/
There are still more to be done on that area, because a lot of things are still in shadows. More research needs to be made.