I rather like the infographic above, sampled from this article by Siobhan Roberts in the New York Times:
Lately, in the ongoing conversation about how to defeat the coronavirus, experts have made reference to the “Swiss cheese model†of pandemic defense.
The metaphor is easy enough to grasp: Multiple layers of protection, imagined as cheese slices, block the spread of the new coronavirus, SARS-CoV-2, the virus that causes Covid-19. No one layer is perfect; each has holes, and when the holes align, the risk of infection increases. But several layers combined — social distancing, plus masks, plus hand-washing, plus testing and tracing, plus ventilation, plus government messaging — significantly reduce the overall risk. Vaccination will add one more protective layer.
or, rather, I like it with a couple of exceptions. My first quibble occurs in the very next paragraph:
“Pretty soon you’ve created an impenetrable barrier, and you really can quench the transmission of the virus,†said Dr. Julie Gerberding, executive vice president and chief patient officer at Merck, who recently referenced the Swiss cheese model when speaking at a virtual gala fund-raiser for MoMath, the National Museum of Mathematics in Manhattan.
“But it requires all of those things, not just one of those things,†she added. “I think that’s what our population is having trouble getting their head around. We want to believe that there is going to come this magic day when suddenly 300 million doses of vaccine will be available and we can go back to work and things will return to normal. That is absolutely not going to happen fast.â€
Uh, no. A safe, effective vaccine will reduce the risk. It will not reduce it to zero which is implied by “impenetrable barrier”. The model originated in industrial safety and even the bloke who devised it in that arena recognizes its limitations. Accidents can be reduced but not reduced to zero. It should also be pointed out that the most successful vaccination program in U. S. history included mandatory vaccination and quarantines. If you believe we will implement mandatory vaccination and quarantines for COVID-19, please explain how you think that’s politically possible. I don’t see it. We can’t even manage to get everybody vaccinated against measles.
My second quibble has to do with the slice labeled “fast, sensitive testing & tracing”. I don’t believe that we presently have fast, sensitive, and accurate testing and will not have such a thing for the foreseeable future. There’s generally trade-offs among speed, sensitivity, and accuracy and I expect that to remain true. I’ll have more about tracing in a later post.
Nonetheless I think the infographic is good and largely good advice with the distinction between personal responsibilities and shared responsibilities being useful.
I like the image too, but I think the reality is that once the vaccines are readily available, most of those slices of cheese are going to drop away. Not instantly, and I’m not sure how best to describe the tipping point, but vaccinated people aren’t going to voluntarily avoid social gatherings and wear masks, and the governments are going to pursue to policies that assume vaccines as the dominant health care measure.
The pandemic will become endemic, partly through vaccination, but also infection. Parts of the U.S. have had 25% to 30% of their population infected, like Illinois, the New York area and the Dakotas. People/governments would be paying or enduring the inconvenience of many public health measures when the disease spread is minimal whatever the cause. And people who experienced the pain or discomfort of a shot won’t either.
I tend to agree with that. A lot will depend on the reaction after the first person dies from an adverse reaction to the vaccine. That’s something that people are missing. I think that some number of such adverse reactions are inevitable. Keep in mind that within six months even with reluctance we’ll have inoculated several orders of magnitude more people than have participated in the trials.
We could have fast effective testing if we made it a priority. We have two levels of testing g in our system. An in house test for which we can get results in 60-90 minutes when we have enough reagents. (We dont right now so we are testing very few people.) We have tests done by the large commercial lab that dominates our area. When they arent overwhelmed we get results in 24 hours. Right now it takes about 5 days, not very useful.
We dont have a story of large scale tracing and local governments dont have the resources to do it. Of course no one answers their phones. I assume all calls that come from an unknown source is from someone selling something, or worse, a political ad or beg for money.
On topic, I think the model is a good one. No one component works perfectly. Even all together it wont work perfectly. I have no idea what happens once people get vaccinated. I have no idea if the vaccine sterilizes or how long it will work. I do agree that people arent going to distance, wear masks, etc. But if the vaccines really are 94% effective if it becomes endemic it does so at much, much lower rates than the flu.
Steve
“Pretty soon you’ve created an impenetrable barrier, and you really can quench the transmission of the virus,â€
Pure bullshit. The writer does not understand dominating variables. A humanities graduate, no doubt………