It depends upon their age and level of health. Me? No danger at all. My mom? Very dangerous due to her 84 years and ill health.
No surprise you have no fucking clue. By all means, never get another vaccination in your life.
Seriously. The more people like you who avoid doctors, medicine and vaccinations, the better for everyone in the long run.*
The fucking bleeding hearts try to save every puppy and kitten in the world. Practical rationalists like myself know that is impossible. Better to neuter animals and require breeding licenses if the goal is to reduce unnecessary proliferation of dogs and cats.
Same logic applies to dumbasses.
*I strongly doubt all the elderly Euro-American males on JPP who constantly whine and bitch are actually avoiding doctors, medicine and vaccinations. It's why I strongly believe they are liars and have no honor.