Every pandemic starts with a single infection. In the case of COVID-19, that infection happened in or near the city of Wuhan in the first days of December, 2019. By the time Dr. Li Wenliang warned his colleagues that emergency rooms in the city were filling up with people displaying a SARS-like illness—and got arrested for spreading “rumors”—the number of people infected had grown to at least the hundreds. By the time Dr. Li died on February 6, the Chinese government acknowledge over 28,000 cases and 560 deaths.
Within the next two weeks, COVID-19 would continue to grow steeply in Hubei province. However, by that time the government had already isolated travel in and out of the area. Other regions of China were also engaged in extensive testing and isolation. The story of the COVID-19 outbreak within Hubei became a story of stressed medical resources, families forced into quarantine facilities, 67,000 cases and 3,000 deaths. But at the same time, no other Chinese province reached even 1,500 cases.
As of Friday, 13 U.S. states—on both coasts, in the north and in the south—had exceeded 1,500 cases. And with no federal leadership on exactly how to handle the virus, states, counties, and cities have been making decisions on their owns. It’s not just creating a nation being crushed by the pandemic, but one where the story of the pandemic is already varying widely.
The COVID Tracking Project is not the best site to visit if your primary interest is the latest big board number showing total cases across the country. But they are a fantastic resource when it comes to state level data, including information on the extent of testing and links to state health departments. Their historical data also allows for states to be compared in ways that are not just interesting, but make it possible to see past the flurry of numbers and show both red flags of alarm along with fingers-crossed glimmers of hope.
Before we dive into states, let’s look at what’s become an all too familiar graph of how the United States is racing ahead of other nations when it comes to total cases.
It’s pretty obvious that, at this point in the story, these nations are having quite different experiences. Not only is China no longer churning out thousands of new cases, the actual number of active cases remaining in that nation is down to around 3,000—a number that would be barely visible on this chart. Italy, which has now joined the United States on the high side of China’s peak, has been under government-enforced rules of suppression that have so far failed to stop the virus, but have definitely given it a different slope than the American rocket ship. Meanwhile, the incredible rise in the United States isn’t just a story of action that was too late and too little, but of testing so inadequate that even weeks into the epidemic, the chart is more a measure of our ability to confirm cases than a reflection of the number of people actually ill.
But take away the big numbers for a moment and look at this same information in a different way.
Well, that certainly looks like … a mess. What’s being charted here isn’t the sheer number of cases, but how one day compares to the next. For example, on Friday the United States had 104,000 cases logged, which is 1.22 times the 85,000 cases on Thursday. It is possible to generate much more interesting and distinctive charts using log scales, log-log scales, or log-log vs log scales. Especially using animation. But those take a lot of explanation, and honestly, I think this one is good enough at getting across the point.
By looking at the numbers not in terms of total cases, but in terms of simple day to day growth, it’s easier to see how effective measures at suppression or mediation are being when it comes to interfering with the growth of COVID-19, no matter what that total case count may say. For example, China and South Korea, way down there at the bottom of the chart, have clearly exited the whole cycle, with effective repression that has them essentially back to square one — watching out for individual cases, and safeguarding against infections brought in from elsewhere. A whole cluster of nations is in the middle of that exponential growth phase, but two in particular tell different stories on this chart.
Italy’s efforts at suppressing transmission of COVID-19 are clearly being effective. Day after day, the rate of increase in Italy is being driven down. Italy reluctantly instituted a national lock down on March 7, after days of trying limited regional solutions. Within five days, their rate of growth began a steady decline. They haven’t actually flatted the curve in the way of Asian countries like South Korea, but they’ve made steady progress. The level of social distancing being carried out in Italy is effective, and if they stay with it, they will soon reach the point where more people are recovering than being added to the case count. With over 9,000 people dead and 66,000 active cases, it’s hard to say that Italy is in any sense “winning,” but the action they are taking is limiting the damage and making it possible for their overburdened healthcare system to see a light at the end of the tunnel.
On the other hand … is us. The United States. Not only are the values in the United States all over the place, they’re almost uniformly at the top of the chart on any given day. The United States has both the largest number of cases, and the fastest rate of growth. There is zero good news to be found in that. And yet … in just the last few days, the overall numbers for the U.S. do seem to be trending in the right direction when it comes to growth. Don’t look at that last down tick (on any such chart, ignoring the final data point is always a good idea, because that data point is likely either incomplete or soon to be revised). What the chart says is that the United States is still doing worse than everyone else. But it’s doing better than it was just a week ago, which may indicate that social distancing measures put in place in many states two weeks ago, are beginning to appear in the data.
So let’s take these same kind of charts, and apply them to some states.
Looking at overall confirmed cases tells a story that looks a lot like the evening newscast — a huge number of cases in New York, with a handful of states very far down the chart, but still displaying scary numbers of cases.
Now … to the growth-snarl.
Look down at the 1.00 flat line and you see … no one. Not a single state has really exited the growth phase of the epidemic. This isn’t just true for those states at the top of the chart, it’s true for those at the bottom. However, the overall number in the United States is being driven by some of those values in the chaos above. All those dots up in the 1.5-1.8 zone represent a doubling rate that’s less than 2 days — a really extraordinary rate of growth that is, again, mostly defined by the ability to conduct tests.
But look past the rather angular spaghetti of the last two weeks, and it is possible to see some trends here. One, Washington State has consistently been at or near the bottom of this chart, despite having been the first place in the nation where COVID-19 was known to be circulating in the community. Like Italy, they haven’t completely flattened the curve, but they have made tremendous steps toward bringing the growth rate under control (and did I already say ignore the last data point? Ignore the last data point). There’s good news for New York, as well. The horrific rates of growth seen a week ago have been moving down toward the national average. This likely indicates some success of social distancing, but also a rate of testing that is finally at least keeping up with the spread of disease.
Now, one more … because I promised.
On Saturday morning, the United States had over 100,000 more cases of COVID-19 than neighboring Canada. Which is, frankly, amazing. Good job, Canadians.
However, looking at the rate of growth, there is definitely cause for concern. As with all data, the day to day figures are erratic, overwhelmed not just by the amount of testing, but also by simple coincidence of which day a particular case was reported. In general, Canada has done a much better job at limiting the daily growth. But the values in the last week show that they are not immune to seeing COVID-19 take off as it has in other countries. Since the 15th, the United States has averaged over 1.3 in terms of growth rate. But Canada has topped 1.2 — which is a land of not-good.
If anything, this is the time for Canada to clamp down harder, test, isolate, and … watch out for people crossing the border.