Why the United States is emerging as the epicenter of the coronavirus pandemic

For several weeks, the question facing the United States was which of those paths we were approaching. Would we be able to contain the virus and limit its scale? Or would we be less able to control its growth, straining our systems? Could we adjust our systems in time?

It’s still too early to answer that question for the country broadly, but it’s clear that, in at least some places, we’re replicating Italy and not South Korea. New York City, for example, has seen a spike in cases and a strain on its hospitals. Washington, once the most-affected state, has been better able to contain the virus.

The interactive below uses per-day data from Johns Hopkins University to compare the spread of the virus in different states and countries over time. (These data are archived as of Sunday.)

We can start with a comparison of the United States, Italy and South Korea.

Your browser cannot display this graph.

It’s immediately apparent how the number of cases in the United States has grown more rapidly even than they did in Italy. If you change “type of data” to “cases per million,” though, the picture is slightly different: As a percent of total population, the United States trails Italy.

Now add New York state. (The state/country selector allows for multiple entries.) As a function of population, the situation in New York is escalating much more rapidly than in the United States generally or in Italy. The lines are colored relative to the average change in the past week. Blue lines have seen limited relative recent growth while red lines get darker as the rate of increase grows higher.

The Financial Times has created a graph that has become the emblematic indicator of the spread by country. You can approximate the Financial Times graph by setting “timescale” to “relative” and “display scale” to “modified logarithmic” on the above interactive. You’ll get something like this, depending on the countries you choose to display.

The flatter a line, the slower the rate of increase in confirmed coronavirus cases. The United States’ line continues to increase at an exponential rate. If you again add New York, you see part of the problem: The growth of cases in the Empire State is faster than nearly anywhere else.

Compare New York with Washington state, and you can see a stark difference.

Washington’s line is significant flatter, which is also why its line is a lighter-colored red than New York’s. The virus is being better contained in that state.

But Washington may be the exception. Add in Florida, Louisiana and New Jersey, and their lines look a lot more like that of New York.

You may notice, too, that we’ve included data from the H1N1 pandemic that emerged in 2009. Set the “timescale” to “relative,” and you can compare the speed and mortality of the current outbreak with contemporaneous reports from that year.

Over the past two weeks, a number of states have sharply constrained public activity with an eye toward slowing the spread of the novel coronavirus. Since it can take about two weeks for symptoms to manifest, the effects of those changes will not be reflected in the data for some time. This is why New York Gov. Andrew M. Cuomo (D) expects infection numbers in his state to continue to rise for the next few weeks.

Here’s where the comparison with Italy is particularly useful. The rate of growth there has slowed relative to the United States after it entered a broad lock down 16 days ago. That’s the hope here, as well, that the broad efforts to contain the virus will help slow the rate of increase.

President Trump’s announcement last week that he was advocating a 15-day period of restrictions was aimed at that goal. The question is how much of an effect those restrictions might have had and whether they were enough to contain the virus sufficiently to prevent the number of cases from increasing again once the restrictions are lifted.

But it’s worth remembering that, even at the end of the 15-day period, we will only have just started to see the effects of that effort in the numbers (barring places were restrictions were put in place earlier). In other words, only as Trump’s window of action expires will the effects of those actions be detectable.

In the meantime, the United States may well become the country with both the second-most cases (after China, where the outbreak began) and the fastest rate of growth of any country in the top tier of those affected by the pandemic.

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