So I linked to one important source I used in my non-professional but (hopefully) mathematically literate guesswork about how COVID-19 deaths in the US will increase over the next while. What I didn’t appreciate at that time was that the graphic that they used to discuss geometric growth in deaths in various countries is a dynamic graphic. Every time a country updates its total deaths on its own official websites, which happens once a day or more for Eurpoean and North American countries, the graphic itself updates. This means you can’t click on the link from a past article (or in this paragraph) and get easy access to the numbers I used when writing a particular blog post.
When I linked that article, it showed total deaths in the USA had doubled over the previous 4 days. But two days past and the graphic is now different. Realizing that I couldn’t use that as a stable record of my thinking, I have decided to take screen shots to have a record of how well the death doublings track with my guesses about how the speed of those doublings will be affected by changing quarantine orders and individual behaviors.
Because stay-at-home orders take 2-3 weeks to show up in death rates, and because Washington, NY, and California have been on stay-at-home orders for a while but large states like Texas and Florida hadn’t issued them until last week, I suspected that death doublings would continue at the same rate until about the 15th to 19th. But I’ve been checking in to see if maybe the states that issued early stay-at-home orders haven’t had their effect yet. Maybe there will be a change in doublings before the red state holdouts begin clamping down on transmission risks?
What I found is that after 2 days the doubling rate is very nearly identical. Total deaths were multiplied by 2.1 over the last 4 days of CDC data. You can see that in the following snapshot of the chart, after clicking the circle-i icon next to the US data:
For the scenario I thought likely (a largely steady doubling rate for the next 12 days, then lengthening slightly to a 5 day then a 6 day doubling period) based on when stay-at-home orders were introduced, the USA would hit a quarter million deaths before the end of the month. Obviously at that point, even if we greatly extend the doubling period, any doubling is a lot more people we lose to death. Also, if you’ve been tracking Trump’s predictions, you know he said the US should expect about 100k deaths and no more than 240k deaths. Hitting the quarter million number on April 29, my guesstimate, would mean we exceed his most pessimistic prediction before the end of this month, with many months more to come before we can expect a vaccine.
I hope I’ve been clear to everyone that I’m not an epidemiologist. I’m just using the publicly available data to track what seems reasonable to me. We’re not doomed to double US deaths three times from April 3rd to April 15, I’m just following what the disease experts say the COVID-19 infection-to-death lag is supposed to be and reckoning that we can’t get any help from the final red state stay-at-home orders until at least then.
This continues to look really, really bad.
I continue to believe that we’re in for a million deaths or more, but all those predictions change if the behavior of US residents changes. More masks, more hand washings, more care when helping others (like leaving packages on a doorstep and backing away instead of bringing food or other necessities into the home of someone we’re trying to help), fewer businesses open, fewer non-mandatory meetings like book clubs and shabbat services: these are all reasonable, possible, incremental changes that can slow that doubling rate. I don’t expect them to have much effect before the end of the month, though.
Why? Because I believe that there are a large number of very stubborn people in the US determined to ignore the risk, some of them for political reasons, some for religious reasons, some for economic or other reasons. I do think that eventually deaths will be so common that if you don’t have one among your immediate family and close friends, you’ll have a friend who does. When we get to the point where everyone knows someone who is grieving I think most resistance to social distancing will collapse. Now, these aren’t predictions that can be checked against math. I don’t know how hard core the resistance to distancing really is, and I don’t actually know how long it will last. I can’t be certain it will stay strong until grieving becomes ubiquitous.
What I can do, though, is keep checking in with that CDC website and provide you an update every few days on how close things are tracking to my original prediction based on April 3rd numbers. In another 6 days we’ll have a good idea about whether 3 doublings by April 15-16 will be borne out. By April 20th I think we’ll be able to be fairly sure whether or not we’ll hit a quarter million US dead by the end of the month. So I’ll keep checking in with the website. If appropriate, I’ll keep updating my guesses about the toll on US residents.
I wish I didn’t have to do this, but it’s obvious that the federal government isn’t releasing updated projections based on real computer models tested against past outbreaks and created by people far more knowledgable than I. So I’m going to keep on updating the numbers, keep on massaging my spherical cow, and keep on hoping that my ignorance of epidemiology really is leading me to dramatically overestimate the ultimate cost to human life and health and happiness.
May you stay safe and healthy.