As the pandemic intensified, the fall continued. On November 10, the U.S. recorded more virus hospitalizations than ever before, passing the previous high set during the spring and summer surges. More than 100,000 Americans were diagnosed with the virus every day last month, on average, and more than ever were hospitalized as well. But as facilities ran short on bed space, the fraction of admitted cases fell. Ultimately, only 7.4 percent of COVID-19 cases were hospitalized in November—the lowest percentage yet.

This change may not seem ominous at first. You might expect to see such a divergence, for instance, if testing rapidly increased, so that states were suddenly detecting many more mild cases of COVID-19. But the data don’t show any evidence of this kind of “casedemic”—if anything, they show the opposite. Last month, the number of total COVID-19 tests increased by about a third compared with October, but the number of total cases discovered more than doubled. More people are getting sick.

At the same time, the virus seems to be killing a slightly higher fraction of people diagnosed with it. Using a method that accounts for clinical- and data-reporting lags between cases and deaths, for most of October and November, about 1.7 percent of cases resulted in death. But in the middle of November, that number lurched to more than 1.8 percent. While this change may seem small, it represents hundreds of deaths, because many more people are getting sick every day.

In other words, we’re observing exactly the opposite of what you’d expect from a rash of mild cases in the data. The virus seems to be killing more people.