Your example is exactly why blinded studies are needed. The are numerous variables that need to be controlled. Observations such as this are the beginning of important findings but follow up is needed. It may be that a common medicine used at the facility has undocumented antiviral effects or another factor is in play.
One of the common antipsychotics appears to be a very potent cancer preventative. This effect was unknown until someone observed that schizophrenics have a very low rate of cancer.
Once again, I am saying that it is presumptive to recommend that people skip vaccination and take an unproven treatment.
Personally, I am taking vitamin D and took the vaccination, belts and suspenders I suppose.
When did I ever say not to vaccinate????