I am bombarded with probability questions from family and friends about COVID. Common questions are:
- What are the chances I’ll catch COVID?
- What are the chances I’ll catch COVID and die?
- What are the chances I’ll die of COVID if I go to a restaurant? If I go to church? At the grocery store?
It goes on and on – these are all legitimate questions from people just trying to figure out how dangerous this thing really is. In fact, all these probabilities are quite low, and in the range of the probability of death from other normal activities.
I thought I’d compare the probability of death from kissing a random stranger with driving a car. Driving a car is an inherently risky activity with more than 35,000 deaths per year in the U.S., but we’ve developed a sense of just how much risk we’re taking verses the benefit of taking that risk. COVID is new and scary, so we just don’t have the ingrained metrics to know how we want to behave. In any event, I estimate the risk of kissing a random stranger about equal to driving 154 miles. I think most of us wouldn’t hesitate to hop in the car a few times and drive a couple hundred miles this week, but not many would kiss the random stranger, which is arguably a bit safer.
So here’s how I did my calculations: I’m currently modeling about 145,000 known and active cases of COVID in the U.S. Or course, this is likely just a fraction of the total people sick with COVID, but we can use the NY study to help us. Back in late April, we knew that about 10 times more people had COVID than those revealed by daily testing. That multiple is likely quite a bit lower now that testing has more than doubled since then. I’ll be conservative and call the multiple 5, so we’ll assume that 725,000 people are sick with COVID at the moment. With a population of about 330 million, that means that the chances that the random American you are kissing has COVID would be about 0.0022, or 0.22%. From my previous mortality work, I estimate the probability of dying from COVID if you contract the disease and under age 60 at about 0.0009, or about 0.09%. Multiply these two together and get the chances of a COVID death from kissing a random stranger at 0.000002, or about 0.0002%.
In the U.S., we lose about 1.3 lives per 100 million miles driven – the chance of dying per mile is about 0.000000013. To increase that probability to that of dying from COVID from kissing a random person you’d have to drive 154 miles. Of course, this would vary considerably by where you live (is COVID widespread or scarce?) what sort of driving you do, and your age, but you get the idea. In general, if you’re young, it’s probably fine to kiss random strangers, but if you’re older, better not.
As always, feel free to send me your questions about my assumptions, methodology, or modeling in general.
- Likely date of active case peak (Chalke modeling): April 10
- Likely date of peak deaths (IHME): April 16 (last revision on May 29)
- Short term projection for active cases tomorrow: 142,000
- Total Test Results reported today: 403,791 (very high)
- Total Pending tests reported today: 3,455 (very low)
- National reported case Growth Rate today: 0.9% (record low)
Shane Chalke Interviews
Groom Ventures has agreed to host a website that will archive my daily reports, and supplement with other commentary. John Groom worked at one of my companies back in the day, and is an excellent writer. The website is: www.howmuchrisk.com For those of you that post my daily report on Facebook, let me suggest you link to this site, as the direct Facebook posts don’t seem to copy the graphs.
Here is the national picture of active cases – continued, slow decline. I suspect it’s declining faster than this graph suggests, as the testing has ramped up so fast we’re now finding cases where people are marginally sick. We know this because the fraction of those testing positive that end up in the hospital has declined dramatically (thank you to Professor Martin Zelder at UNC for showing me this). I’ll continue to work on a credible method of adjusting for this. Until then, I’ll continue to model active cases from the raw total case data.
Here are the new reported cases nationally. All still tracking in the right direction.
Here are the daily reported tests. We’ve set several new records recently, with no weekend slowdowns…
Here are the daily death reports. Daily deaths are falling steadily. Today’s report was the lowest in over 2 months. You won’t see that in the news…
On to the states. It’s always interesting to look at VA and NC side by side, as the states are quite similar except for the degree of lockdown.
No surprises with Washington – drifting upward lately. The numbers are small, and Washington has had several previous episodes of increases.
Florida has been more or less flat for 2 weeks now. The hot spot in Florida continues to be Miami. Other than in SE Florida, COVID presence is small.
Well, look at that! NY state now below 9,000 cases. That’s less than ½ of California now. NJ is looking good too, with less than 6,000 cases. NY is now down 87% from the peak, which is remarkable. Both states are recovering well.
California continues to be problematic. CA is now similar to NY on a per capita basis. IHME now projects that the California daily death count doesn’t peak until June 27th, so California could be rising for another week or two.
Massachusetts continues to do well, with a remarkably rapid recovery. MA didn’t report today, so expect a bump tomorrow. Massachusetts is now down 78% from the top.
Georgia’s decline is painfully slow, but continues to follow the trend.
Michigan has been flat for a few days, but remarkably, down 67% from the peak on April 6th.
Continued, almost straight line, decline in Pennsylvania today, 60% below their peak.
Up and down the past few days in Texas. I believe Texas peaked on May 19th. Texas has a small COVID presence per capita.
And finally, here is Colorado. Colorado is one of the states that has had aberrations in their data. It’s showing about flat for 2 weeks, but I’ve shied away from any conclusions in this state due to the data irregularities.
So that’s it for today. The numbers are very small as a percentage of the population. Unless you’re in a high density area, your chances of contracting COVID are very small. However, even though the probability is very small, that doesn’t help if you’re the one catching it. Everyone please continue to be as cautious as circumstances dictate.
–Shane Chalke, FSA