Everyone knows that we are cleaner for the washing of our hands. The childhood fibs of our parents that potatoes will grow behind our ears if we don’t wash there regularly have been pretty much dismissed. There was little evidence for the benefits of washing behind our ears other than the authority and wisdom of parents but for most of one’s life that’s enough (or at least till we turn and mistrust everything our parents say).
In Australia, OHS has been pushing for evidence-based decision making. Some have twisted this noble aim into short-term empire building on concepts such as a “body of knowledge” (- the more important question should be why do particular people want to control this knowledge in the first place). But evidence is important and over the last few years some researchers have been seeking the evidence for the safety benefits of hand-washing in infection control, particularly during times of epidemics or pandemics.
The current swine flu scare (it remains a “scare” in many parts of the world) is generating recommendations on personal hygiene, as reported in SafetyAtWorkBlog on yesterday, but is there evidence or is hand-washing a comforting distraction?
Earlier this year Jody Lanard and Peter Sandman wrote:
The “Cover Your Cough” page on the CDC’s seasonal flu website begins this way:
Serious respiratory illnesses like influenza, respiratory syncytial virus (RSV), whooping cough, and severe acute respiratory syndrome (SARS) are spread by:
- Coughing or sneezing
- Unclean hands….
If you don’t have a tissue, cough or sneeze into your upper sleeve, not your hands.
We have been unable to find a single study that supports this recommendation with regard to influenza. The World Health Organization Writing Group report on “Nonpharmaceutical Interventions for Pandemic Influenza” makes the same recommendation for flu specifically, but concedes that it has been made “more on the basis of plausible effectiveness than controlled studies.”
As for hand-washing, a Mayo Clinic publication on hand-washing includes flu on a list of infectious diseases “that are commonly spread through hand-to-hand contact.” The Government of Alberta’s “Influenza Self-Care” publication advises: “Wash Your Hands to Prevent Influenza…. Next to immunization, the single most important way to prevent influenza is to wash your hands often.”
But here’s what the World Health Organization Writing Group report says: “Most, but not all, controlled studies show a protective effect of handwashing in reducing upper respiratory infections…. Most of the infections studied were likely viral, but only a small percentage were due to influenza…. No studies appear to address influenza specifically.”
The Lanard/Sandman article discusses at length the way that hand-washing may be affecting our approaches to other control measures such as vaccination. It tries to cut through the hyperbole on influenza and if you are a health care worker, the full article is strongly recommended.
At the moment there is no clear evidence of the benefits of hand-washing and if this swine flu scare remains a scare for most people, one of the areas for further research should be the effectiveness, and role, of hand-washing in the control of pandemic infections. It just may be that “universal precautions” should not be so unquestioningly universal.
There IS however evidence that repeated/frequent
handwashing (particularly with >60% alcohol or with
>20 seconds lathering soap) leads to marked to severe dermatitis with breakdown of the stratume corneum aannd even deeper, leading to fissuring of
the skin. Damaged/cracked skin will harbour orders of
magnitude more infectious particles than does intact
skin. Furthermore, severe dermatitis will lead to
disability and loss of income for those who work with their hands…
I do not have references at my fingertips, but all the above IS evidence-based and in the peer reviewed
literature.