Wednesday 27 July 2016

Don't wash your hands?

I've learned how to behave from some unlikely sources and some of results have seemed to buck the trend. You don't need to add stones to mountain cairns, for example. Second-hand books and second-hand clothes are perfectly fit for function. I hear now that second hand books have a very short life in hospitals. If they stay in the bring-one-take-one library they can be read multiple times but if they are once taken off the trolley in a ward, then they are marked for incineration because they are now contaminated.  Hmmmm, I'll have to hunt out the evidence for disease-by-book because it looks like optics to me. C. diff  Clostridium difficile is a major player here and I wonder if demonising books lets health-care professionals off the hook with hand-washing. And why do doctors wear neck-ties on ward rounds? C. diff is called difficile because it's damned difficult to keep it alive outside of the mammalian gut.

Now it turns out that the US Food and Drug Administration FDA is going after handwash. For years antiseptic handwashes and ditto rubs [the difference is that the rubs stay on; the other is rinsed off] have been generally recognized as safe and effective (GRASE). But since the last review of over-the-counter OTC handwash products in 1994, a lot has changed. Such things are being used a lot more often for starters, and technological improvements can now detect smaller residual traces of the chemicals.  In 1994 the approval rug was pulled from under hexachlorophene, which was the active ingredient in pHisoDerm an OTC acne treatment widely used when I was a teenager.  pHisoHex 3% is now available on prescription only.
At the same time phenol, fluorosalan [see L for structure; aka 3,5-dibromo-3¢-trifluoromethylsalicylanilide] and tribromosalan [3,4,5-Tribromosalicylanilide] were also de-GRASEd.  Phenol was the first effective antiseptic, used by such luminaries as Joseph Lister FRS (1827-1912) back when it was called carbolic acid. In the face of puerperal fever, pneumonia and fatal staph infections, phenol was a godsend. It saved lives immediately - pity about it being carcinogenic later on.

Taking out those effective but no longer safe enough chemicals left less brutal (and probably less effective) antiseptics based on ethanol (booze alcohol), isopropanol (just like ethanol but with 3 carbons not 2) and benzalkonium chloride (which you find in your bathroom/kitchen as a component of Dettol and Lysol. The latter's MSDS form looks pretty frightening: "Very hazardous in case of skin contact (irritant), of eye contact (irritant), of ingestion, of inhalation. Hazardous in case of skin contact (corrosive), of eye contact (corrosive). The amount of tissue damage depends on length of contact. Eye contact can result in corneal damage or blindness. Skin contact can produce inflammation and blistering. Inhalation of dust will produce irritation to gastro-intestinal or respiratory tract, characterized by burning, sneezing and coughing. Severe over-exposure can produce lung damage, choking unconsciousness or death. Inflammation of the eye is characterized by redness, watering, and itching. Skin inflammation is characterized by itching, scaling, reddening, or, occasionally, blistering." But the FDA is now proposing to crank up the grading of all three products to IIISE. This category throws complacency out of the window and the current push by the FDA is to seek actual evidence that they really are S (safe) and E (effective). The FDA is a at pains to say that we should all carrying on using these handy products until the evidence is in - so the call is purely precautionary.

I heard a very strange radio advert last week from the Food Safety Authority.  They fingered "those over the age of 65" as having weakened immune systems; it also implied that people of such venerable age were getting a little ditsy in the head. They were urged to wash their hands in warm soapy water for 20 seconds before approaching food. "20 seconds is the time it takes to recite Happy Birthday to You, twice" just in case the old dears have forgotten to take off their watches while washing in warm soapy water. I'll report in 3 years time if there is such an abrupt transition in immunological and cognitive function when I turn 65.

I wash my hands very little: looks like I might be right and Lady Macbeth was wrong.

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