“I see vaccinations as the problem,” Rabbi Shmuel Kamenetzky told the Baltimore Jewish Times in a story published in late August. “It’s a hoax. Even the Salk [polio] vaccine is a hoax. It’s just big business.”
Kamenetzky argued that schools should not exclude unvaccinated students, as they currently do under public health laws. He also claimed that school janitors would be spreading disease if vaccines worked. “They are mostly Mexican and are unvaccinated,” the rabbi said. “If there was a problem, the children would already have gotten sick.”
This is the inevitable result of taking the idea of "Da'as Torah" way too far.
Men like R Kamenetzky have no expertise whatsoever outside of their deep Torah knowledge and their piety. And they live fairly cloistered lives, so are unaware of responsible literature on science, medicine, and many other fields.
But when your followers believe that being a talmid chacham magically makes you somehow an expert in all disciplines, perhaps you begin to believe it yourself, resulting in ignorant statements like this.