What do you do about adults that have not vaccinated? I expect there are far more unvaccinated adults around than childrenas vaccination was only routine for things like polio when a lot of the now adult population were children.
Most adults will have had a lot of the same vaccines that children have now as in the 1970s and 80s children were routinely vaccinated against diphtheria, tetanus, pertussis, measles, mumps, and rubella.
This is when the common UK vaccines were introduced:
Hib/MenC - 2006
Measles - 1968
Mumps - 1977
Rubella - 1970
MMR (to replace the above three) - 1988
Pneumococcal (PCV) - 2006
Diphtheria - 1942
hepatitis B - 2017
Hib (Haemophilus influenzae type b) - 1992
Polio - 1955
Tetanus - 1961 (this is when it was added to the childhood schedule, it was available from 1950s)
Whooping Cough - 1950s
Rotavirus vaccine - 2013
Many of the adults who were children before various vaccines were introduced will have either caught the disease and have immunity that way, will have been picked up in catch-up programmes or as a result of circumstances (e.g., being given a tetanus vaccine after a wound breaking the skin), for some women they'll have been caught up in pregnancy (whooping cough vaccine) or postnatally (MMR vaccine if 10wk bloods showed no immunity to rubella). They will also be protected by herd immunity.