180 years ago, a doctor in the Austrian Empire conducted a radical experiment that has saved millions of children but cost him his life. This shocking, ground-breaking experiment involved doctors washing their hands. I know, I know, it sounds ridiculous, but doctors not only didn’t wash their hands back then, they were opposed to the very idea so much that the researching doctor was institutionalized and beaten to death. In this article, we’ll explore the history of handwashing, how they came up with the experiment, why people weren’t washing their hands in the first place, why the experiment worked, and how modern hand washing works. Then, we’ll dive into some nitty-gritty science.

Handwashing is old. Like, it’s really old. We have good evidence of soap from nearly 3000 years ago. Handwashing as a ritual before meals is in Abrahamic religious texts. It was recorded in ancient Egyptian and Greek civilizations and is even practiced by raccoons. But this was superficial handwashing, mostly meant to get rid of visible dirtiness because we hadn’t discovered germs yet. Instead, ideas of how disease spread were based on things like miasma – the stinkiness of a dirty thing.

Ignaz Semmelweis was a physician who, in the 1860s, got a residency in a maternity ward. In those days things were separated by gender, so there were two clinics. One was attended by male doctors and one by female midwives. Dr. Semmelweis noted that people died in the male-run clinic at a rate 300% higher than in the midwife-run clinic. He was appalled and wrote that women would have better outcomes giving birth in the street than in the hospital. The primary disease causing all the deaths was childbed fever, now known as (pew-er-per-al) puerperal fever. Luckily, Dr. Semmelweis had a shocking (shocking!) insight. He theorized that perhaps the fact that the doctors would do autopsies before going to the maternity ward was causing some of the “cadaverous particles” to infect the patients. He got this idea when a fellow doctor cut himself during an autopsy and subsequently died of childbed fever. Dr. Semmelweis concluded that doctors should wash their hands in chlorinated water upon entering the maternity clinic! Within a year the death rate plummeted from ~10% to under 2%.

Unfortunately, doctors were reluctant to change their ways. The theory that doctors could be killing their patients was seen as offensive and came with the implication that doctors were unclean, which went against the class system of the era. He was reluctant to release his findings, but when he did they were dismissed and his reputation was ruined. In his book Die Aetiologie, der Begriff und die Prophylaxis des Kindbettfiebers, he is racked with guilt. He was committed to an insane asylum where he was beaten to death by the orderlies within weeks under suspicious circumstances. It would be decades before germ theory gave an explanation for Semmelweis’s findings and brought them back into the public consciousness. He would never know how many millions of children and mothers he saved.

In Dr. Semmelweis’s day, they used chlorinated water to wash their hands. Let’s dive into modern-day hand washing. How does washing hands work? Why do we need to wash our hands, even if they look clean? Are there better ways to wash hands? Is hand sanitizer just as good? To start, let’s look at the skin as an immune organ. The skin is awesome. It’s our biggest organ and is the primary defense against invading germs; the tiny microorganisms like bacteria, fungi, and viruses. The skin has three major defense mechanisms. Our immune cells fight organisms that get too close for comfort and our skin hardens and sloughs off, taking bacteria and viruses with it. Before either of those, potential attackers have to deal with the skin microbiome. It turns out our skin isn’t just a cool canvas for tattoos but is an entire ecosystem for thousands and millions and billions of teeny little friends that make a living harvesting our sweat or whatever. Three important genera of bacteria take up the bulk of what we call the resident flora: cutibacterium, staphylococcus, and corynebacterium. These three coat our skin and enhance the immune protection skin gives us. They are commensal organisms, which is kind of like the mob. We give them food and shelter, and they promise to (mostly) do us no harm. They are called “residents” because they live with us our whole lives. They colonize our skin, making it hard for other invaders (called transient flora) to get a foothold. The defense mechanisms they have for themselves work well against the transient flora. In addition, they break down cholesterols we emit into free fatty acids which keep our skin a little acidic, killing invaders. They tend to reside deeper in the skin layers than transient bacteria, are less likely to cause infection, and are harder to remove.

This is exactly where handwashing shines. Transient flora, like MRSA, multidrug-resistant gram-negative bacteria, Vancomycin-resistant Enterococci, and “cadaverous particles” tend to be closer to the outer layers of skin and are easier to remove. Effective hand-washing removes the transient flora but keeps the residents intact. Even more effective than just soap and water are antibacterials. These attack the transients in creative ways, degrading the cell walls, DNA, and proteins. Hand sanitizer is effective at destroying many bacteria and can be applied frequently and without a sink. So next time you wash your hands between visiting the morgue and the maternity ward, think of Dr. Semmelweis and thank him for his experimental vision!

Staff Writer / Editor Benton Lowey-Ball, BS, BFA

References:

Boyce, J. M. (2021). Hand hygiene, an update. Infectious Disease Clinics, 35(3), 553-573. https://doi.org/10.1016/j.idc.2021.04.003

Edmonds-Wilson, S. L., Nurinova, N. I., Zapka, C. A., Fierer, N., & Wilson, M. (2015). Review of human hand microbiome research. Journal of dermatological science, 80(1), 3-12. https://www.sciencedirect.com/science/article/pii/S0923181115300268

Skowron, K., Bauza-Kaszewska, J., Kraszewska, Z., Wiktorczyk-Kapischke, N., Grudlewska-Buda, K., Kwiecińska-Piróg, J., … & Gospodarek-Komkowska, E. (2021). Human skin microbiome: Impact of intrinsic and extrinsic factors on skin microbiota. Microorganisms, 9(3), 543. https://doi.org/10.3390/microorganisms9030543

Semrnelweis, I. (1861). Die Aetiologie, der Begriff und die Prophylaxis des Kindbettfiebers, C. A. Hartleben’s Verlag-Expedition, Translated by K. Codell Carter. Madison, 1983 https://archive.org/details/b28064045

Widmer, A. F. (2000). Replace hand washing with use of a waterless alcohol hand rub?. Clinical infectious diseases, 31(1), 136-143. https://academic.oup.com/cid/article/31/1/136/317796