The Path of Covid Deaths: The Virus Chart that Forecasts the Future

Cases are still rising during this wave of the pandemic. Deaths are probably not far behind.

The number of Covid-19 deaths in the U.S. has dropped in the last few days, but there is reason to think the decline is a statistical mirage — and that deaths are on the verge of surging again.

Why? The relationship between confirmed new coronavirus cases and deaths has held fairly steady this fall. If you track the number of new cases, you can fairly accurately predict the number of deaths three weeks later. Every 100 new cases in the U.S. has led to an average of about 1.7 deaths, with that three-week lag.

It’s not a precise equation, of course. The time between diagnosis and death in fatal cases is sometimes shorter than three weeks and sometimes longer. And the death rate is not exactly 1.7 percent. But that simple formula has done a striking job of describing the path of Covid deaths in recent weeks.

The chart here shows the relationship — daily deaths compared with an index equal to 1.7 percent of newly diagnosed cases from three weeks earlier. The two lines have risen almost in tandem for the past three months:

The most likely explanation for the tick down at the end of both lines is the statistical mirage I mentioned: There was a slowdown in testing over Thanksgiving weekend, which may have artificially reduced the number of both reported coronavirus cases and deaths.

“Thanksgiving has really blurred the picture."

Mitch Smith, a Times reporter who tracks the virus statistics, told me.

In coming weeks, deaths seem almost certain to rise, perhaps sharply. The run-up in cases during November suggests that daily deaths may approach 3,000 in December. The previous one-day high was 2,752, in April, and the previous high in the seven-day average was 2,232, also in April.

Already, the U.S. death toll in recent weeks has exceeded one victim every minute of every day — 1,462 deaths per day in the two weeks before Thanksgiving. Barring a major surprise, that toll is about to get even worse. And January is looking worrisome, as well.

Dr. Anthony Fauci, the infectious disease expert, said yesterday that Thanksgiving gatherings may have created clusters of new infections.

“We might see a surge superimposed upon that surge that we’re already in."

Fauci said.

An explainer: Andrew Joseph of Stat walks through the timeline of how an infection turns into a serious illness.