Semmelweis, born in Hungary in 1818, started working at Vienna General Hospital’s maternity clinic in 1846 after graduating from medical school. Before long, he became deeply unsettled by the extraordinarily high maternal mortality rate in one of the wards.

In the ward that was staffed by physicians and medical students, 13 to 18 percent of new mothers were dying of a mysterious illness known as the childbed fever, or puerperal fever, according to a BMJ article summarizing his research. By comparison, in the ward staffed by midwives, about 2 percent of women died of the fever. No one knew what explained the extreme discrepancy.

So Semmelweis started digging. He scrutinized everything from the climate to the crowds at each maternity clinic, trying to pinpoint factors that might cause a spike in fever cases at one. But the only obvious difference was the midwives.

What were the doctors doing to the women that midwives weren’t?

“Everything was in question; everything seemed inexplicable; everything was doubtful,” he wrote in his book in 1861, “The Etiology, Concept and Prophylaxis of Childbed Fever.” “Only the large number of deaths was an unquestionable reality.”

Finally, he made a startling realization. A fellow doctor died of what appeared to be a case of childbed fever after cutting himself with a scalpel that had been used during an autopsy of one of the women.

The physicians, Semmelweis realized, had been dissecting infected cadavers with their bare hands. Then, with those same contaminated hands, they were delivering babies.

“They were inoculating their patients with bacteria,” Perlow said. “They were basically immersed in pus for hours.”

The science of bacteria was not yet understood. But Semmelweis was getting close to his answer. He believed the autopsy physicians must be carrying around invisible particles of “decaying animal-organic matter” on their fingers. So he required anyone examining a woman in the labor room to wash their hands in a chlorinated lime solution before entering, especially those who had just touched dead bodies.

Within months, the results of this simple hygienic change were apparent and astounding. The maternal mortality rate dropped to 1 to 2 percent, matching that of the women in the midwives’ ward.

Could the simple act of washing hands really be responsible for saving all those lives?

To some of Semmelweis’s colleagues in the medical community, it sounded crazy.

Dana Tulodziecki, a philosophy of science professor at Purdue University, told The Post that it sounded radical to some because of the prevailing ideas about how diseases spread. Back then, she said, people believed in the “miasma theory,” that wafting toxic odors were largely responsible for spreading diseases through the air. If people cared about washing their hands in earlier decades, she said, it was because they were trying to get rid of the smell, not the particles.

Now Semmelweis was claiming that those invisible particles on doctors’ hands were to blame.

“Nobody was pleased to think that doctors were responsible for killing all these women,” Tulodziecki said. "Nobody liked that. Especially because the ward with the midwives had a lower mortality rate, but of course the doctors were supposed to know much more than them.”

Still, Tulodziecki stressed that Semmelweis was not alone, or first, in identifying the possible link between childbed fever and unsanitary practices by physicians. Most notably, Oliver Wendell Holmes Sr. wrote a paper suggesting that the link in 1843, and James Young Simpson in Britain also independently studied it around the same time as Semmelweis, Tulodziecki said. But in the broader medical community, Semmelweis had a messaging problem. He couldn’t seem to communicate why hand-washing solved the problem.
(clipped from above article)


He was not an 'expert' so much as a guy who saw results with his own eyes, but since he wasn't educated enough, and couldn't explain exactly why his method worked, his ideas were dismissed, and even ridiculed, even something as simple as washing hands to prevent disease spread.  
The idea that experts will dismiss an idea, simply because the idea came from someone not as smart or educated as themselves, was even named after him.  
https://chronotopeblog.com/2015/06/06/the-semmelweis-reflex-why-does-education-ignore-important-research/