The quite interesting story of the development (over many decades) of the HPV vaccine:

But each step forward to those techniques was a triumph of hard science over the pseudoscientific myths that for centuries surrounded the disease.

The first was posited by a doctor in Florence in 1842. He noticed that prostitutes and married women died of cervical cancer, but nuns almost never did. Though he might have discerned that it was sexually transmitted, he was thrown off by another fact: nuns often died of breast cancer. His conclusion was that nuns’ corsets were dangerously tight.