By all indications, the United States is entering its fifth surge in this coronavirus pandemic, with new case counts near their all-time high and seemingly still on the ascent. Here are the graphs, from Google and the New York Times, for both new case counts and new death counts over time:
We’re going to focus on the death count here, for a few reasons. First, the inconsistency of test availability makes cases a more uncertain indicator of the virus’s prevalence than deaths (though there’s evidence—check out The Economist’s excess death tracker if you’re curious—that deaths have also been undercounted over the pandemic as a whole). Second, as our ability to treat this coronavirus has improved, the disease has effectively become less severe, in the sense of each individual case, making deaths a stronger reflector than cases of the disease’s stress on our medical systems, a relevant concern. Third, deaths are, in the end, the thing we want to prevent. We don’t want people to die. We don’t want people to get sick, either, but deaths are the ultimate focus.
Within that death count, then, we see five surges. The first is sizable—the virus’s initial outbreak, beginning back in March of 2020. The second is the smallest—2020’s summer surge. The third is the largest—last winter’s, seemingly cut off in its tracks by the distribution of vaccines across the early months of 2021. The fourth came at the onset of this fall, attributed to the delta variant. The fifth, this one, is more visible right now on the graph of new cases than the graph of new deaths, possibly because it’s so early and cases are a leading indicator of deaths (that said, the data on omicron’s severity is promising, though whether that will be outweighed by its contagiousness remains to be seen).
It’s a terrible thing, death, and we don’t want to take it lightly. By all indications, a lot of people are about to die from this variant who would not have otherwise died this early in their lives. This is very sad, and it’s the biggest reason we hope this surge will be as short in duration and small in impact as possible. In addition to that reason, though, we want these things because of our own desire for normalcy, for business reasons, for reasons of personal stress, for valid reason upon valid reason. Death is the worst thing, but other things are also bad, and the pandemic has brought plenty of the latter alongside plenty of the former.
With that, then, let’s try to take a guess at when this surge will end.
There are two ways to look at this, as far as I can tell, and for both we’ll be using the CDC’s seven-day moving average of Covid death counts.
The first is to look at the distance between each peak and each valley on that graph above. Here’s what that yields:
- The first minimum in the average daily death count came 62 days after the first maximum.
- The second maximum came 39 days after the first minimum.
- The second minimum came 61 days after the second maximum.
- The third maximum came 105 days after the second minimum.
- The third minimum came 173 days after the third maximum.
- The fourth maximum came 72 days after the third minimum.
- The fourth minimum came 73 days after the fourth maximum (this may have been artificially hastened in the data by Thanksgiving delaying death reporting, but the valley appears to have been at least around November 27th, if not on that exact day).
- The fourth minimum was now 31 days ago.
Put differently, it’s taken us an average of 54 days to get each surge in deaths to peak, though last winter’s peak came 105 days after last fall’s valley, and the delta peak came 72 days after this summer’s valley. After the peak, we’ve seen decreases for an average of 92 days before deaths start rising again, though again, the variability is high. If this surge were to behave perfectly averagely by this metric, deaths would peak on January 20th and then hit their valley on April 22nd. There are plenty of reasons to doubt this—seasonality, omicron’s specific transmissibility and/or deadliness, the impact of still-increasing vaccination rates, the impact of how omicron affects the vaccinated and unvaccinated differently, on and on and on—but that’s the general outlook, looking at things through this lens.
The second way, which I prefer, is to look at how long each surge gave us death counts above the all-time average, which for us, using that CDC data, comes out to roughly 1,125 deaths per day, taken from the seven-day moving average from January 23rd, 2020 through December 26th of this year. In short, for how long in each surge were daily death counts, on average, above 1,125 deaths/day?
- In the first surge, the death count moving average spent 50 days above the 1,125 deaths/day threshold.
- In the second surge, the death count moving average spent 13 days above our threshold.
- In the third surge, the death count moving average spent 124 days above our threshold.
- In the fourth surge, the death count moving average spent 75 days above our threshold.
- It’s currently been 24 days since the death count moving average’s first day above our threshold, though it’s hovered around the line, spending ten of the 23 days measured in that window back below the 1,125 number.
The average here, then, is 65.5 days spent above average, which would point to deaths receding below that 1,125 mark again on February 8th. There are reasons this spike could last longer—the last two surges have been the longest, with last winter’s covering the same time of year we’re currently in. There are reasons this spike could be shorter—this is the first surge in which we’ve hovered around the threshold rather than immediately climbing past it and staying past it for the duration of the surge. There’s so, so much uncertainty here. We really don’t know, and as has been the case with each of the other four surges, this one is unique, both in terms of the variant’s biology and in terms of our response. Much remains to be seen. But if you want to use the prior surges as indicators, this is what they tell us: If this surge is comparable to the previous four, deaths should rise for at least a few more weeks, and things should remain bad, relative to these last two years, through sometime around early February.
