A Few Certainties About Covid-19


There is plenty that we do not know about the coronavirus. But let us take stock of the things that we do know for sure, and of some other things that we will soon know.

Real-world Exponentiality

By now, a child understands exponential growth. If you start with one apple on March 1st and double every three days, you will have a thousand apples on March 31st and a million on April 30th.

But in the real world, not the abstract world of math, there are constraints on that growth. Doubling your apples every three days is feasible for a month or so because you can probably find a thousand apples and also find a place to store them. But it would be more difficult to find, transport and store a million apples, unless you are willing to pack a six car garage with apples from floor to ceiling (accurate math). If you did, most of them would rot and your neighbors would call for psychiatric help, two other constraints on unbridled exponentiality.

Similarly, the real-world constraints on the exponential growth of coronavirus cases are either 1) a saturation of the population, when all the people susceptible of being infected are infected, or 2) human intervention that stalls the spread long before we reach that saturation.

The first case, saturation, means that say 50 to 80% of the population would get the virus, or 165 to 265 million people for the United States. Assuming a 1% fatality rate, this would result in 1.7 to 2.7 million deaths, an unacceptable death toll. Further, the fatality rate may be higher than 1% when hospitals are overwhelmed.

If you approach the question with more granularity and apply a different fatality rate for each age group, you also end up with an unacceptably high death count. It is true that coronavirus deaths have occurred mainly among elderly people who had comorbidities, but these lives were a long way from ending. The average age of the dead in Italy is about 80 years, but life expectancy in Italy at age 80 is nine years.

Any death is “unacceptable” but here, we are measuring this total against the incremental number of deaths that would result from a continued shutdown or slowdown of the economy. We are in the midst of another pandemic of what Princeton Professor Angus Deaton has called ‘deaths of despair’, deaths from suicide and substance abuse. We would not shut down the economy for a peak of 10,000 coronavirus deaths, and indeed we do not shut it down every year for the estimated 25,000 to 60,000 fatalities that result from the seasonal flu.

Because “letting it burn” would exact a high death toll, governments all over the world have opted for the second constraint on exponential growth, human intervention to kill the spread. Home confinement has delivered the wanted results in China and looks on track to stall the spread in Europe. Below is the daily growth in confirmed cases in Italy and France over the past three weeks (smoothed over five days).

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Sami J. Karam is the founder and editor of populyst.net and the creator of the populyst index™. populyst is about innovation, demography and society. Before populyst, he was the founder and manager of the Seven Global funds and a fund manager at leading asset managers in Boston and New York.