Even Rabbi Nachman of Breslov, who denounced physicians in the strongest terms, saying that when the Angel of Death understood that he could not kill everyone by himself, he appointed the physicians to do it for him (Sihot HaRan 50), did not oppose medicine per se.
He himself claimed, on another occasion, that a father who does not vaccinate his son against smallpox is a murderer.
–Rabbi Adin Steinsaltz (from Talks on the Parasha, Bereshit)