## Playing Six Degrees of Separation with SARS-CoV-2

by James Wallace Harris, Sunday, March 22, 2020

This morning I got up and decided to think positive about our situation.  First, we have to consider the numbers. I like to use rules of thumb to make easy comparisons, so here’s a table based on a world population of 7 billion. (It’s really 7.7, but I’m making it easier on myself mathematically.)

Population Percent
7,000,000,000 100%
700,000,000 10%
70,000,000 1%
7,000,000 .1%
700,000 .01%
70,000 .001%
7,000 .0001%
700 .00001%
70 .000001%
7 .0000001%

I feel looking at the math should reduce our fears — at least for now. Using nCoV2019.live for my stats, worldwide there are 323,117 confirmed cases of SARS-CoV-2 this morning. That’s about .005% of the population. 13,848 have died, or about .0002%. Now, I no longer trust my math skills, but I believe that’s 1 in 505,488 for dying, and 1 in 21,664 for being infected. Those numbers make me feel better.

Of course, that’s using the total population of the world. If you live in Italy or New York City, your chances are much greater at being infected or dying. The U.S. has roughly 327 million citizens, meaning if we only consider it, which has 27,684 infected people with 354 deaths as of 3/22/20, then there’s a 1 in 11,812 chance of being infected, and 1 in 923,728 of dying. Still not bad. However, the population of NYC is 8,623,000, and if all 12,683 infected cases from New York state were in the city, that’s only 1 chance in 680. Now, they are starting to get scary.

Depending on where you live, you might feel your odds are pretty good.

During the initial stages of a worldwide pandemic, your chances of being infected increases by how many people you know who travel. Remember the Six Degrees of Separation game? Right now, most people outside of Wuhan who have caught SARS-CoV-2 were just one or two degrees away from meeting someone who recently flew. At first, it was people who traveled from China, but now it’s more about people coming from Seattle or New York City, but eventually, it will be about the people who drive around your city.

I don’t know anyone who has the disease. It takes One Degree of Separation to catch Covid-19. I don’t know how close the plague is, it could be two, three, or even four degrees away. Things will get much more frightening when we know people who know infected people — two degrees away. So far, I don’t know any two-degree people or even heard of any three-degree people.

The reason why China has been able to contain the disease is that it tracked every connection. The U.S. has allowed the disease to get out of control, which means they can’t track the various degrees of separation. However, by getting everyone to shelter in place they could get the pandemic under control again and then start tracing the infections.

Some states and smaller cities might be able to track all the cases of infection and keep things under control. But that won’t work unless people stop moving around. The reason why the game Six Degrees of Separation actually works is humans love to travel. It’s why the pandemic spread so quickly.

I wonder what we will learn from this lesson. When a pandemic breaks out, we should stop all air travel immediately. That means travelers will get stuck in foreign cities for the duration. We won’t know how far we’re willing to go until this pandemic is over and see its total cost. Besides killing a lot of people, it will probably devastate the world economies. That might make us savvier about the next time.

It’s been about a century since the last terrible pandemic. It would be comforting to think another horrible pandemic won’t come around for another century. However, humans are increasingly doing things to up our chances of another pandemic. We could be more careful if we wanted. It’s a matter of science, education, and statistics.

I wonder if this pandemic will teach us the value of science. Too many people dismiss science because it reveals unpleasant statistics. I found this cartoon on Facebook that should remind everyone of the true value of science. It got only one like by my friends when I reposted it.

JWH