Only if you willfully didn't vaccinate: Otherwise, it is just that: 1) You are poor and can't afford medical treatment in time. 2) Very young and haven't been

Only if you willfully didn't vaccinate: Otherwise, it is just that: 1) You are poor and can't afford medical treatment in time. 2) Very young and haven't been vaccinated 3) Not young, but don't have immunity for a variety of reasons, including unable to be vaccinated and immune system issues. 4) You are simply unlucky