Weird science

The astrophysicist Neil deGrasse Tyson likes to say that the great thing about science is that it's true whether you believe it or not.  That proposition has been tested to the breaking point during the coronavirus pandemic as expert advice, from the WHO down to your local health authority, seems to have lighted on a different definition of the truth on almost a weekly basis.

Masks!  From the outset of the pandemic, the advice has been to wear masks whenever social distancing is difficult, particularly in indoor settings. We should do this, so we were told, not because the masks protected the wearer from inhaling the virus, but because they helped reduce the quantity of virus particles that an infected person might breathe out and pass on to others.

This never did seem entirely logical. Layers of fabric don't have any way of distinguishing whether a wearer is breathing in or out.  If a mask can intercept virus particles on their way out of the lungs, it seems more than likely that it can also intercept some on their way in. 

Lo and behold, the Centers for Disease Control (CDC) in the United States are now admitting this. This week the CDC has updated its guidance on mask wearing: it now says that cloth masks act both as a "source control" to limit exhalation of virus particles, and as "filtration for personal protection" to limit inhalation of particles shed by others. The new guidance quotes various studies on the benefits of increased mask usage, including the suggestion that a 15 percent increase in mask usage could prevent economic losses of as much as $ 1 trillion.

A lot of people have been conscientiously following masking rules for many months now, so does this  change of heart really matter? It almost certainly does. In societies with relatively limited social cohesion -- a category in which I would include most of the developed world, including the US and Canada -- asking people to do something purely for the benefit of others is not going to work for a significant portion of the citizenry. Asking them to do it for their own health and safety is likely to produce a much higher level of compliance. If the CDC had issued this advice months ago, and if it had been backed up by local health authorities, it's not hard to imagine that many thousands of lives would have been saved. 

Still, better late than never, right? Not necessarily. It's a safe bet that there are plenty of people out there who will ignore the CDC's advice -- I mean, you're admitting that what you told us all along was wrong, so why should we believe that you've got it right now?