David Wallace-Wells writes:

A few weeks ago, in a back-of-the-envelope calculation during an interview with Eric Topol of Scripps, I suggested that because of widespread vaccination of the most vulnerable elderly, we may have reduced overall mortality risk in the country by 90 percent. Topol thought that was a little high, but agreed that vaccines were delivering great protection against death and hospitalization, and while we would likely see some of each during the Delta wave, “it won’t be like the monster third wave.” More recently, the Dartmouth economist Andrew Levin, who early in the pandemic did major work calculating mortality risk by age, estimated in an interview with my brother that the effect was probably 75 percent — that given the same number of cases, we’d probably see about one quarter as many deaths as we would’ve seen a year ago, without vaccines.

The U.S. numbers are a bit wobbly these days, and there are huge variations state to state, reflecting disparities in vaccination rates, among other things. But at the national level, at least for the moment, the reduction of mortality risk seems to be considerably smaller. In the worst of the winter surge, the country was registering 250,000 new cases per day; at its peak, that surge was killing roughly 3,000 Americans each day (often a bit above, but with a few dips below). Today, we have a bit more than 100,000 new cases each day, though the numbers are still rising as part of the Delta wave. If we had reduced mortality risk by 75 percent, that would mean about 300 daily deaths. If we had reduced it by 90 percent, it would mean 120. Instead, in our seven-day average, we just passed 500.

Things may be even worse than that, though. In general, epidemiologists expect a lag of a week or two, perhaps more, between case peaks and death peaks — essentially the time it takes for a new case to progress through the full course of disease. Early in the pandemic, the lag was a bit longer, though in the U.S. during the winter surge, the gap between peaks was less than one week. And comparing case data from even one week ago with today’s death data reveals an even grimmer picture: about 75,000 cases per day then yielding the current average of 500 deaths, suggesting the mortality rate had fallen by less than half since winter. If you work from two-week-old data, it suggests that the mortality rate had hardly fallen at all. Applying the winter ratio to the case load from July 24 would predict an average of 600 daily deaths. On Friday, there were 763.

For a couple weeks now, concerned Americans have taken comfort in the Delta experience of other countries, namely the U.K. and the Netherlands, whose Delta waves had begun earlier and who had — very roughly — similar vaccination rates to ours. In those countries, as models would have suggested given our expectations for vaccines, caseloads dramatically diverged from hospitalizations and deaths, with case numbers growing much, much faster than severe disease, which stayed, all things considered, pretty low. That simply does not seem to be happening here, even though the vaccines are working well enough that hospitalization and death remain, for breakthrough cases, very rare. Could these trends reflect rates of under-testing? To some extent, of course. But how much?

On Saturday morning, looking at Friday’s figures, I emailed Topol to ask if he was as worried as I was. Yes, he said. We spoke again later in the afternoon. [Continue reading…]