[Oh, my. Thanks to my readers at CIDRAP (tip of the hat!) I have become aware the story linked below on masks is an old one, something Crof at H5N1 calls a ghost story. The NewsNow aggregator I use has been doing this a lot lately, so I have been alert, but in this case I had it in my head there was a new mask report and I didn't check the date carefully. Everything I said in the post is still true, but it isn't new. In fact I said much the same thing when it first came out -- a year ago! Anyway, my apologies to readers. I hate to make mistakes like this.]
The National Academies os Science’s Institute of Medicine issued its final report on the use of masks should there be a pandemic with influenza/A H5N1 and it wound up pretty much where interim an earlier did: they don’t really know if masks will work and how well.
The problem, as before, is that we don’t know the main modes of transmission of influenza from person to person. Is it by touching inanimate objects like doorknobs or shaking hands that have virus on them? We know the virus can remain viable there but there is little evidence people actually become infected that way. But it’s plausible.
For a long time we thought it was spread via “large droplets,” i.e., the big virus laden drops emitted by a cougher or sneezer. Those droplets are relatively large, aerodynamically speaking, and fail to the ground within feet of where they are emitted. They also don’t get down far into the lungs. They’re too big to negotiate the twists and turns of the upper respiratory tree. Thus if they are the route of infection, they infect the upper tract first. Also plausible. A surgical mask can stop them from being emitted and block them from being inhaled.
Then there are the very tiny particles. These can remain suspended in the air for extended periods and travel relatively long distance from their source. Imagine them hanging in the air of a bus or an Emergency Room. They can get deep in the lungs and pass easily around the edges of a surgical mask. In principle, the disposable N95 respirators will stop them, but to be effective these masks have to be carefully fitted to each user and if you have any facial hair, forget it. They also don’t come in pediatric sizes. And if inanimate objects are an effective route of transmission, they have to be handled carefully because the outside of the mask will be contaminated from others sneezing in the environment.
So where does that leave us?
If a worldwide flu epidemic strikes, don’t reuse a face mask – and don’t assume, either, that it will offer a lot of protection, the Institute of Medicine said Thursday.
That’s the bottom line from an anxiously awaited probe requested by the government as it stockpiles supplies in case a flu pandemic begins. (AP)
The real bottom line is that we better get busy and strengthen our public health and social service infrastructures because we’re not going to get by this one by hiding in a bunker or wearing a mask 24/7. We’ll only get through this together.
Better to start planning for that now.