Coronavirus: the “Doubling Time” of Deaths per Day
Today, I started to see the numbers tick up for Coronavirus – for New York, for Chicago, and for the nation overall. I’m watching the numbers in Indiana as well, as most of my extended family and loved ones are there.
This caused a lot of anxiety for me, as I just see the number of reported cases are growing. It’s difficult to watch what looks like a rising tide, and be unable to do anything about it. To know that inaction (staying at home) is, ultimately, the only course of action. It’s really frustrating.
A few things I’ve read lately have suggested two things. First, the number of cases and deaths are going to rise. They have been, and will continue to do so. I think we’re going to see a very significant rise in numbers this week, and the next.
Part of this rise is due to the fact that we’re testing more people (a positive thing). But it’s also due to the fact that we are now seeing the impact of people who were infected a week ago, and perhaps didn’t know it. And for that period of time, those people may have unwittingly spread it to even more people, who we won’t hear about until next week.
If you haven’t seen it yet, I urge to spend a few brief minutes and listen to Dr. Emily Landon summarize the Coronavirus epidemic, and talk about why it’s so imperative people stay home.
One post on Twitter I encountered today seemed to help me, with the anxiety I feel on seeing the growing number of cases. Before we get into that, I want to say this: there’s a lot of information out there, from people who may or may not be experts.
Review your sources. Question them. And I urge you to also question my source here, as I’m still uncertain how I feel about this. I feel comforted by the take, but that’s not good enough. I feel like this information is trustworthy. And while I did do my due diligence, I urge you to do the same. And trust this not because I shared it, but because you find it also trustworthy.
Once again: DO NOT TRACK THE NUMBER OF CASES. THIS IS SUPPOSED TO INCREASE AS TESTING COMES ONLINE.
Instead, track the number of deaths per day. If the “doubling time” of these slows to more than 3 days, we’re starting to bend the curve.
— Sam Wang (@SamWangPhD) March 21, 2020
So the take is this: the number of cases will most definitely rise. But they’re unreliable, in that more people are being tested, and so the number will inflate as a result of that increased testing. Also, the cases reported will not account for those who do have the virus, but have not yet been tested.
A clearer number to look at is the number of actual deaths from Coronavirus. Those deaths are easier to identify (respiratory distress). The first symptoms appear around 5 days after contracting the virus, and death tends to occur within 14 days after the first symptom.
The chart above looks at the past 14 days, and determines how long it took for the total number of deaths to double in a given country. Currently in the United States, where many states have just begun issuing “stay at home” orders, we’re seeing the total number of Coronavirus deaths doubling every 3 days.
In countries like Italy, that are hard-hit but currently well into their “stay at home” orders, the doubling time is around 5 days.
In countries like China and South Korea, who have been battling Coronavirus longer and been more successful in getting citizens to remain at home, the doubling time is in the double digits.
Sam Wang posits that if we started to see the doubling time in the US increase beyond 3 days, that means we’ve been successful in “flattening the curve.” And that our efforts to isolate ourselves is having an effect.
This sounds great to me, and makes me feel a bit more at ease regarding the rising number of cases and deaths I see. But I’m not a stats guy. Once more, I highly suggest you look at these references and determine for yourself whether you find them credible and trustworthy.
I fear the coming week and the one after will show our country some very grim numbers, and that we will start hearing some very terrible, sobering stories. But I hope that the actions we take to protect both ourselves and one another will help stem this tide. And that we will, indeed, see an increase in that doubling time.