COVID-19 Across America: It’s the Geography, Stupid!
The COVID-19 dialogue in media, medical and political circles is driving me crazy. It is unnecessarily spooking an entire nation. I feel particularly badly for the children who are too young to critically evaluate what the adults are spewing at them and for the elderly who have been made to feel in mortal danger. The dominant narrative is of the deadly second wave.
We fought and largely defeated COVID. But then because we eased up, the killer has escaped. Now there is a deadly, out-of-control second wave. We should have kept the lockdown going. Irresponsible Governors, especially in red states, and cavalier citizens are causing this out-of-control second wave.
This narrative just is not true. There was a northern wave of COVID-19 that experienced its peak lethality in May and a southern wave which is cresting right about now (with some variation from southern state to state). There is no pattern related to political persuasion of governor. There is one wave per geographic jurisdiction.
Importantly for the path of COVID-19, the US has multiple geographic jurisdictions with dramatically different climates. It has a large population with dense urban centers living in a geographic band with very cold winters. And it has another large population, also with dense urban centers, living in a band with warm temperatures entirely or nearly year-round (plus a third band in between). This geographic population structure has had an impact on the spread of COVID-19.
The easiest way to see the impact is to compare the states that border on Canada (Washington, Idaho, Montana, North Dakota, Minnesota, Wisconsin, Illinois, Indiana, Michigan, Ohio, Pennsylvania, New York, Vermont, New Hampshire and Maine) versus the states that border on Mexico/Gulf of Mexico (California, Arizona, New Mexico, Texas, Louisiana, Mississippi, Alabama and Florida). The northern band has politically near-equal governorships (8 Blue and 7 Red), the southern band a little more lopsided (5 Red to 3 Blue). The 8 southern band states have slightly higher population at 113 million vs. the 15 northern band states at 100 million. I have used data from this site to analyze the waves and the data is summarized in the chart below.
The Northern Wave
With one tiny exception, the northern wave crested (which I define as hitting peak seven-day moving average of deaths) in a 7-week period between April 10 and June 2. The exception is Montana which missed the northern wave entirely and had its peak — with a modest 3 deaths/day — on August 2. Twelve of the 15 states are clearly in the tail of their curves with the collective daily deaths for August 7 (the day I cut off this analysis) at a tiny 8.5% of their respective peaks. In these twelve states there is no sign of a second wave. Two of the three exceptions are Montana (above), and Idaho, which had a mini-peak of 4 deaths per day in April and has already gotten past its second peak of 8 on August 1. While every death is unfortunate and should be mourned, the numbers involved are so small that it is hard to argue that they represent actual trends as opposed to statistical noise.
The only northern state that can be described as having any kind of meaningful second wave is Washington, which peaked at 28 deaths per day on April 10, dropped to 5 per day in June and is back up to 13 as of August 7. Thus, the total extent of the northern second wave is an increase of 8 deaths per day in Washington State — hardly the cause for national uproar.
The Southern Wave
With a couple of exceptions, the southern wave was minimal (proportionate to state population) in the April-May timeframe and these states are experiencing their first peak right now, lagging the northern wave by two and a half months. The fact that their deaths are rising or have peaked recently is not evidence of a second wave of COVID-19. It is evidence that the southern states couldn’t escape the fate of the north — which is to experience a single wave of COVID-19. Five of the eight have seen their first wave crest at some point between July 18 and August 5. California has not yet seen its wave crest. One of the two remaining states, New Mexico, is small with very small numbers. It had a first wave that crested at 11 deaths per day on May 15 and had a second mini wave that crested with 6 on August 2. The only state experiencing a meaningful second wave is Louisiana, which experienced its first crest with 66 deaths/day on April 18 and has not crested its second wave which was at 36 deaths as of August 7 (again seven-day moving average). The explanation of Louisiana’s two waves is pretty simple: the first peak was driven by Mardi Gras. The second peak was driven by the southern wave. Without Mardi Gras in February, Louisiana would have almost certainly been a prototypical southern wave state.
Red State/Blue State
There is simply zero correlation between performance depending on the political party of the Governor of these 23 states (12 Red and 11 Blue). If curve-flattening is the goal, the key measure is the height of the state’s peak as a proportion of its population. For the Blue State Governors, the median peak across the 11 states is 5.2 deaths/million population. For the Red State Governors, the median peak across the 12 states is 5.2 deaths/million population: remarkably identical performance. If one wanted to be critical of Blue State governors, the mean is much higher (11.0 to 6.5) due to the poor results of the Governors of New York (49.3), Michigan (15.1), Louisiana (14.3) and Pennsylvania (12.7) — the four worst performers of the 23 states. But from a statistical standpoint, I find the median more indicative when trying to discern a systematic difference based on political party.
Policy Effectiveness
There is mixed news on policy effectiveness. The country utilized three main policy levers to limit infection during the northern wave: lockdown, social distancing and mask wearing. Lockdowns began in late March and were lifted, depending on the state, in April, May or June — around the time the northern wave crested and started down the tail. Social distancing was encouraged beginning in early March and has continued through the present. Mask-wearing was actively discouraged until early April and then has been encouraged or mandated ever since.
The biggest policy difference with the southern wave was that lockdowns had completely ended before the commencement of the southern wave. With respect to the other two, social distancing and mask wearing were both in place before and during the entire southern wave.
To compare performance, the peak of the northern wave was 16.0 deaths per million population while the southern wave was 6.5 — a dramatically better performance (though if California hasn’t peaked yet the southern wave number will edge higher). The northern wave number is inflated by the unfortunate results in New York, as mentioned above. If New York is left out of the northern wave, its number drops to a peak of 7.9 deaths per million population. With that subtraction, the southern wave states still perform 18% better in flattening the curve than the northern wave states.
The relative performance really shines a critical light on lockdown. It is just hard to argue that the lockdown was critical to saving lives when it was in place for the northern wave and not at all for the southern wave, and the southern wave performed better. Perhaps the greater ubiquity of social distancing and mask wearing contributed to the superior southern wave performance, but it is hard to tell whether the southern wave actually experienced greater adherence to the two measures. I hope the adherence was higher and that it helped lower the death counts. Perhaps research will provide a definitive answer on that front. I suspect the greatest positive impact was on treatment protocols where the learnings from the earlier northern wave provided a treasure trove of clinical treatment help for the southern wave.
But the only unambiguous policy implication from the data is to avoid complete and utter stupidity: don’t send known COVID-19 patients to nursing homes; and don’t slobber over a bunch of strangers at a giant month-long street festival.
The Bottom Line
The dominant narrative is tragically misleading and shameful. There isn’t a second wave. COVID hasn’t made a comeback. It isn’t raging out of control. I have provided detail on the 23 northern/southern wave states, but I also took a more cursory look at the other 25 continental states that are geographically in the middle and the pattern is largely the same. It produced only two substantially sized states (to join Washington) with any hint of a second wave: Virginia with a first wave (peak of 34) and a second smaller wave (peak of 23) and Nevada with 11 and 13, respectively. Of the 32 states that are big enough to have experienced at least one seven-day moving average of 10 or more deaths, there are only 3 states (Washington, Virginia and Nevada) with a combined second wave peak of 49 daily deaths. We need to understand what has happened in those three states to make sure it doesn’t happen anywhere else. But again, while every death is tragic, in a country of 328 million these very small second waves do not constitute a scary trend.
Collectively, those with the loudest megaphones should stop unjustifiably terrifying the nation. The message needs to be:
Sadly, no part of America has been able to escape COVID-19. But, half of the country is already in the tail-end of their curves and the remainder will be soon. Keep wearing your masks. Make sure to thoroughly practice social distancing. But stay calm.
* Seven-day Rolling Average, ** Median Date, *** Average Peak Deaths/Million
