What are we doing to ourselves?

An interesting idea emerged from conversation over dinner with a colleague recently: While it is clear that hand hygiene is foundational for both hospital and community infection prevention, there may be an immunological price to the now all-pervasive focus on hand hygiene in the general population.

Let me explain. Hygiene is one of the pillars of public health and infection prevention, though we still struggle to practice what we know globally. Semmelweis showed us the need for clean hands in the clinical environment, and the notion of ridding hands of germs has evolved since then. Today, alcohol based hand rubs (ABHRs) are prominent in daily life. People rub their hands with "hand sanitizer" before eating out, after riding the bus, after using the restroom, and even at their desks throughout the day. What could possibly go wrong with such an awareness of hand hygiene?

Potentially, nothing. The importance of hand hygiene is undisputed and indisputable in infection prevention. That said, I often see people using ABHR very frequently throughout the day and it makes me wonder if such use of ABHR is eroding not only the transient flora of our hands, but also the resident flora. What is on our hands ultimately ends up challenging the immune system, via oral ingestion, absorption through rubbing the eyes, or inoculation via scrapes and cuts on the hands and fingers. Constantly challenging the immune system with a diversity of biologic agents gives rise to broad immunity.

Might we be eroding the frequency and diversity of that challenge, and thus the strength and diversity of the immunological protection, with such pervasive use of ABHR? This general notion, that cleanliness might have deleterious, unintended community-level consequences, is not new. It's been discussed within the context of polio, for example, and there is speculation about inverse relationships between cleanliness and asthma.

I'll close by noting that ABHR is but one of the several tools society currently employs to kill the spectrum of microbes in our immediate environment. There are also antimicrobial wipes and antimicrobial soaps. The weapons of mass microbial destruction are many and proliferating. They obviously have their place in the clinic but, regarding their sometimes near-obsessive use in the community, are they helping or hurting us in the long run?

(image source: David Hartley)

Semmelweis and hand hygiene

Dr Ignaz Semmelweis was a Hungarian born physician who worked in Vienna in the 1840s. He is popularly credited with the discovery of the importance of handwashing, though perhaps it's more accurate to say that he was among the first to appreciate the importance of hand hygiene, rather than handwashing.  Harbarth (2000) points out that

. . . many scientists have cited Semmelweis' observations, but, amazingly, grossly misleading impressions still arise about Semmelweis and his original idea of antiseptic hand disinfection, often wrongly cited as “handwashing” in the English-language literature. In fact, Semmelweis never promoted handwashing with soap and water; he was opposed to it, since he wrote: “The cadaveric particles clinging to the hands are not entirely removed by the ordinary method of washing the hands with soap.… For that reason, the hands of the examiner must be cleansed with chlorine, not only after handling cadavers, but likewise after examining patients”

Indeed, Semmelweis promoted a policy of using a solution of chlorinated lime (calcium hypochlorite) on the hands between autopsy work and the examination of patients, as opposed to soap.

So, let's celebrate Semmelweis' insights about the importance of the hands in infection prevention rather than associating his name with handwashing alone. He's recently come back on Twitter to help us -- and certainly we need that help. The WHO's World Hand Hygiene Day is May 5. Check out how you can help raise awareness about hand hygiene.

(image source: WHO)

Raw milk and name calling

I've seen several bumper stickers recently espousing the virtues of drinking raw milk. Although selling unpasteurized milk is illegal in most states, you'll find a virtual counterculture that has rejected pasteurization if you search around the Internet. Depending on the website, there are claims that raw milk alleviates allergies, remedies digestive problems, and reduces susceptibility to asthma.

Many of these sources attempt to justify such views with evidence and logic that few clinicians, microbiologists, or public health practitioners would find compelling. In some ways, such views are akin to those voiced from the anti-vaccine movement: They tend to latch on to the occasional, single study with limited findings as scientific validation of their beliefs, while discounting a substantial scientific literature identifying the risks. The truth is that the practice of drinking unpasteurized milk threatens the health of anyone consuming it, especially children and pregnant women.

It's critically important to understand these views (to the extent possible) and not simply write off the people believing them as belonging to a lunatic fringe and call them dumb and stupid. There are raw-milk advocates who eventually come to realize the risks they are taking and change; isn't it better to understand that process and avoid alienating people who might ultimately do the same?

I am reminded of a BMJ Quality & Safety article about Ignaz Semmelweis and the birth of infection control. At the end there is a passage that discusses the inadvisability of trying to convince people of anything by using insults, public humiliation, and haranguing. In talking to (and about) those who advocate drinking raw milk, we should watch the rhetoric. There's a difference between communicating risk and alienating people. Good risk communication can be effective, whereas alienation probably reinforces the behavior in need of modification.

(image source: David Hartley)