“Suppression and Mitigation Strategies for Control of Covid19 in New Zealand”
It’s a paper linked to by a news source I’ve never read before, “The Spinoff,” but it caught my attention because I know one of the authors, Mike Plank, from the whitewater kayak club. He’s a math professor at the University of Canterbury, and a member of the organization called “Centre for Complex Systems and Networks, which has been doing some epidemic modeling for the NZ government.
The math paper was my Delight of the Day…which might tell you something about how the rest of the day went. But I was really quite impressed with the clarity of the “executive statements” (the main points) of the paper. Mathematicians don’t sugar coat things.
Basically, without a vaccine, the way the epidemic ends is that enough of us get the infection (and the subsequent immunity to re-infection) that the transmission rate slows to less than new person getting sick from every infected person (because infected people are surrounded by mostly immune people), and the disease dies out. An optimist might note that if the infection rate stays below 1 for any reason for long enough, the disease eventually dies out….doesn’t technically have to be herd immunity. Wash those hands!
“Suppression” (meaning social distancing, quarantines, closed businesses….what we’re doing now) can only delay an epidemic, not prevent it. When control measures are relaxed, the subsequent spike in infections is just as high and steep….just as overwhelming to the health care system.
“Mitigation” means slowing down the epidemic so that at any given time there are enough hospital beds for all the people who need them. It entails letting the control measures up just slightly so the infection progresses, then clamping down again, repeating that cycle again and again. That graph, with numbers run for NZ (500 ICU beds in NZ, and a host of other assumptions around transmission rate and hospitalization rate), extended out to 2022. Two and a half years.
There’s a gem of a quote near the end of the paper. Paraphrased: “The only other countries that have so far succeeded in getting transmission low enough for mitigation to work are China and South Korea, using extremely intensive measures, including electronic surveillance of their citizens. No western democracy has yet succeeded in reducing their transmission low enough to slow down their epidemic.”
So, I’m not sure what the end game is with all our social distancing. Two years is an awfully long time.
Give It A Burl 
We were discussing it a few days ago on a walk with friends. That, okay, we all understand limits on ICU capacity, and that social isolation slows the transmission and flattens the peak. But… what’s the end game? To isolate until a vaccine becomes available? To isolate until the entire society will “rotate” through and develop immunity? How long will that take?
Thank you for linking this paper. It was good to get at least someone’s idea on what we’re doing, and for how long we’ll be doing it for.
Also, not sure what Jeremiah’s take on this is, but working from home when kids are around – jesus.
Glad to see you writing again. I’ve missed your humour 🙂
How are you guys going, Maria? Are you all home at the moment? Is there peace between Lorelei and Elias?
This is a very interesting way of approaching this epidemic. Not sure what I think of it, but honestly, I don’t feel that the US has had long enough to show whether our mitigation is working or not. It’s just a smidge too early to completely tell, but we are certainly optimistic that the peak will occur in a couple of weeks because we ARE using fairly tight mitigation measures (stay at home/essential travel only). Thank you for all of your blog posts. I read every one of them – they are such fun! Love you and praying for you to continue to find “delights” as you are all home together.
Hi Susan, have you got some good craft projects on while you’re home? Or is the piano getting a work-out?