I have spent umpteen hours on trying to make this message simple. None of that has been aided by the way that the CDC, the WHO and now the UN use the terms and words confusingly to convey messages to the public. The message is often delivered as if they were sitting around their meeting rooms talking to other health and science professionals. In my opinion, we all look to these guys for simple clear and consistent messages. Right now they need to do much better to convey complex concepts, simply, quickly and more often. Education helps prevent panic, mistakes and conspiracy theories (well-as much as anything can anyway).
So here is another attempt by me to get this wording into line with what the rest of world can make sense of.
I could also really use your input to make this work - so leave a comment below, or Tweet me @MackayIM or email me or send me a carrier pigeon - with how to make this message simpler for you and your kids and your grandparents and that weird uncle you stay clear of at Christmas, to understand.
Let's crowdsource a solution to this confusion, help out others and then see if the major public health bodies can come on board.
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| Propelled droplets versus a cloud of suspended. |
Public health speaking is very public.
Public health issues are spoken about on a global stage, more now than ever. It is up to us to better define the right words and use them consistently. That has definitely not happened for "aerosol" and "airborne".
We professionals can't just sit back and expect our stakeholders to come along with us for the ride - they will get confused when imagery conflicts with lingo and official statements, and when different public organizations disagree with each other or use tiny but significant differences in their language to communicate risks.
People are not stupid and deserve more respect than they are currently getting from those who should know much, much better about how to work alongside the public (public health and all).
So what is the problem here?
Droplets would probably be an ideal word to differentiate from airborne - and it has been used to differentiate the level of precautions of personal protective equipment (PPE) to prevent infections - droplet precautions and airborne precautions - but the evil physicist types have ruined the use of that word for us by introducing droplet nuclei (the part of the aerosol that lingers in the air and can convey those viruses that survive in it, to a new person to infect them). Physicists like technicalities.
So the problem is trying to define a name for that other process that can simply and clearly describe infectious disease transmission of viruses & bacteria that are propelled from/by the sick person, across the gap between them and an uninfected person, measurably infecting the recipient. The name should make clear that it is a different process to the one that sees a person get sick by inhaling infectious viruses or bacteria held aloft by the air, in a cloud, made by a previously ill person, that has been hanging around for perhaps an hour or more. That one is an airborne route of transmission.
Some people have berated me for talking technicalities and semantics in recent days while I try to better define this. Tough! Water off an influenza-host's back. Words have meaning and impact and useful words are needed. Especially when everyone is freaking out over a disease they have only read about in dramatized books or seen in Hollywood blockbusters. The two processes listed above are distinct and different for some viruses & bacteria. But it is biology and nothing is 100%, except death.
Some infections, like those leading to influenza, could result from both processes. Some, like Ebola virus disease have never been observed in humans via one route (airborne), whereas there is a defined risk of them occurring by the other (direct contact between a range of virus-laden body fluids propelled onto a mucous membrane). Yes, coughing a tiny barely visible droplet onto someone else's mouth is direct contact between the wet fluids and the mucous membrane.
They two processes are battled differently. We protect ourselves from them differently. And names can tell us about the different levels of risk. But what is that other route to be called?
I have an idea. First some perspective.
Ways to think of the differences.
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| A word cloud of ways to think of the two different processes of spreading viruses or bacteria that result in infection and disease in humans. v2 Thanks to Nina West for good analogy (Fog/Rain) |
The idea.
How about we call the process of relatively short (up to about 3m) distance, coughed/sneezed/vomited wet droplet transfer of disease-causing doses of viruses or bacteria, "Propelled"?
Over to you, world.
Some greats from the comments below...
- "void the spray and live another day"
- Only touched by air, no need to care. Where it splatters, that's where it matters
