Keep It Clean

September 18, 2009

Anyone who has not been living in a cave or at the bottom of the sea for the last few months has probably heard at least enough about the threat of a pandemic of H1N1 influenza (“swine flu”).  We’ve been treated to blow-by-blow accounts of vaccine development, and discussions of what does or doesn’t qualify as a pandemic that occasionally seem more like medieval theology than science.  But, as Tara Parker-Pope points out in the New York Times,  there is one thing each of us can do that has the potential to help a lot; it will even benefit you if you never come within miles of a case of swine flu.

… one of the most powerful weapons against the new H1N1 virus is summed up in a three-word phrase you first heard from your mother: wash your hands.

The Mayo Clinic says that washing your hands regularly, or using an alcohol-based hand sanitizer if conventional washing isn’t possible, is perhaps the single most important habit for good health:

Hand washing is a simple habit, something most people do without thinking. Yet hand washing, when done properly, is one of the best ways to avoid getting sick.

Many pathogenic bacteria and viruses can survive on surfaces like tables, desks, and telephones for an hour or more.  Once the organisms have been transferred to your hands, it is very easy for them to be transferred to your face, around your eyes, nose, or mouth.  Many studies have shown that the average person, without consciously realizing it, tends to touch his or her face every few minutes.  This provides an infection pathway, not only for respiratory illnesses like colds and flu, but also for a variety of gastro-intestinal ailments.

And you do not have to be around obviously sick people to pick up something nasty.  A recent study in Britain [abstract] found that many commuters were carrying infectious agents on their hands:

This study investigated fecal bacteria on the hands of commuters in five UK cities. Of the 404 people sampled 28% were found to have bacteria of fecal origin on their hands.

The 28% figure was the average over the whole sample; in some areas the proportion was as high as 57%.  Apart from the “Ew-w-w” factor, this is another indication that infectious organisms can survive in the open and be transferred by hand contact.

For all those reasons, the Centers for Disease Control and Prevention, with other health organizations around the world, urge frequent hand washing with soap and water or alcohol-based hand sanitizers.

Ordinary soap and water (preferably warm) will do just fine.  There is no evidence that special “anti-bacterial” soaps provide any advantage for routine use, and there is some concern that promiscuous use of those products might contribute to the evolution of antibiotic-resistant organisms.  (And it should also be noted that products advertised as “anti-bacterial” are usually not effective against viruses – like influenza.)   If soap and water are not available,  alcohol-based hand sanitizers do a good job, as long as there is not a heavy accumulation of grime on the skin.

The benefits are significant, especially for a preventative measure so easy to carry out.  Various studies have shown reductions in infection risk from 20% to 60% in various settings.  For what it’s worth, since I started, about ten years ago, being more diligent about washing my own hands, especially when returning home after being out in a public place, I have reduced my frequency of colds by about two-thirds.  Now I do understand that the plural of anecdote is not data, but it’s easy and cheap to try.  So wash those hands.

Again with the Threat Colors

September 18, 2009

When I started writing this blog, I decided that I would steer clear of political issues; there are already plenty of political blogs out there, and I didn’t think just raising the noise level would be all that constructive.  However, there are some issues which, though to some extent politically connected, display such a degree of bipartisan idiocy that I really feel compelled to comment.

Wired has an article about a proposal to change the color-coded threat levels published by the Department of Homeland Security.  The current system, with its five levels, was set up in 2002 in the wake of 9/11; the level has been changed 17 times since then.  The current threat level is Yellow – Elevated,where it has been for three years.  The threat level for air travel has been Orange – High for the same time.

The system has a superficial similarity to the “DEFCON” system of alert levels used by the US military.  There is, however, a significant difference: whereas each of the DEFCON levels (1-5) is associated with specific actions to be taken in terms of preparedness, force protection, and the like, there have never been any particular specific actions associated with the different color levels.  It is also far from obvious what, for example, an Orange alert level means (is it better or worse than Lemon-Lime?).  Bruce Schneier (who also has a blog post on this) wrote in his excellent book, Beyond Fear (2003):

Terrorist attacks are rare, and if the color-threat level changes willy-nilly with no obvious cause or effect, then people will simply stop paying attention. And the threat levels are publicly known, so any terrorist with a lick of sense will simply wait until the threat level goes down.

As he has also pointed out, keeping people in a vague state of dread about unspecific threats is not too far from a definition of the terrorists’ objectives.

The Homeland Security Advisory Council has submitted the proposal for change, citing the public’s apparent disregard of the current system:

“There is currently indifference to the public Homeland Security Advisory System and, at worst, there is a disturbing lack of public confidence in the system,” the council wrote Janet Napolitano, the Homeland Security secretary.

This is a very good summary; or, rather, it would be if the word “disturbing” were changed to something like “refreshing” or “reassuring”.  That the public does not pay attention to this nonsense indicates that they have more sense than I sometimes give them credit for.

The recommendation for fixing the system is risible: the proposal would eliminate the two lowest threat levels (Green and Blue), with Yellow becoming the default, meaning “Guarded: General Risk of Terrorist Attack”.  In other words, it will work better with three levels than five because five is too confusing.  As Bruce Schneier says, “I hope you all feel safer now.”  (I am glad to say that there are some members of the Advisory Council who favor scrapping the whole thing, as I do.)

Especially in tough economic times, we should not be wasting money on this foolishness.  (It is reminiscent of the observation that generals are inclined to plan how to fight the last war effectively.)  As a general proposition, it is much better to spend resources on improving emergency services, which are needed and useful in all sorts of emergencies (not just terrorist incidents, but hurricanes, earthquakes, and wildfires), rather than trying to devise defenses against specific attacks.

The New York Times has a mildly amusing OpArt piece on revising the system.

Update, Friday, 18 Sept., 15:30

I had not seen this page at Wired when I was writing the original post.  But it makes sense.  If we want members of the public to be more sensitive to the threat level, we should use colors that are more, well, sensitive.

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