Finally, Some Good News. This Week in COVID-19 Data, Aug 20

This week, for the first time in more than two months, all our major COVID-19 metrics improved at the same time. New cases have been falling for four weeks, but the country also saw testing declines for two of those weeks, which made it hard to understand whether the declining case numbers really reflected a drop in infections. This week, tests rose as cases fell—a strong indication that COVID-19 transmission across the country may be decreasing. The number of people hospitalized with COVID-19 has also continued to drop, making this the most encouraging week in COVID-19 data since cases and hospitalizations plateaued in early June. COVID-19 deaths, too, have slightly declined week over week, but remain stubbornly high, with 7,235 lives lost this week alone.

Testing Variation

Tests per positive—the average number of tests needed to find a single positive case—rose this week in the South, a good indication that the falling cases in that region are not solely due to the volume of tests. As of this week, all four major US regions are now above ten tests per positive.

Unfortunately, ten tests per positive is equivalent to a 10 percent positivity rate—still twice as high as the WHO recommended in May for governments to consider reopening. Comparison across US regions is instructive here: this week, it took almost 70 tests to find a single positive case in the Northeast, but fewer than 15 tests to find a positive in the South and West. The size of this gap illustrates why schools may be able to open for some in-person instruction in a state like New York without resulting in the immediate discovery of new case clusters, while the opposite remains true for many schools in states including Alabama, California, Florida, Georgia, and Tennessee.

The data we compile from 56 jurisdictions is never perfect, but some of the largest data quality problems we’ve encountered with individual states in recent weeks have eased. Storm-related reporting problems have cleared up in Florida and other states on the Eastern Seaboard. California has worked through the system failures that led to a backlog of thousands of unreported cases. Officials in Texas have acknowledged that their testing and positivity rates will continue to be incorrect for an unknown period but at least the state has publicly recognized the errors.

Good news from hospitalization data

Nationally, the number of people in the hospital with COVID-19 is down more than 27 percent from the peak on July 23rd. Hospitalized patient figures are falling in every US region except the Midwest, where they have remained just above 6,000 for a month.

The decline has been driven by major drops in our four early-summer hotspot states of Arizona, California, Florida, and Texas. Though the switchover to reporting standards set by the HHS made this data more unstable over the past month, declines of this magnitude do appear to reflect an improving reality on the ground.

Our gains are fragile

Amid the cautiously good news at the national level, we remain concerned about the number of recent peak cases happening in the Midwest. Tests have risen greatly since April and May, but the fact remains that many Midwestern states are seeing cases rise.

At the national level, it may be useful to recall that cases were declining, if slowly, as reopening began across the country in early May. Though US testing capacity has clearly improved since that time, cases and hospitalizations are nonetheless much higher now than they were two months ago. In areas where second reopenings are not closely tied to continued testing progress, reductions in cases, and other critical data, we would expect to see increased transmission followed by rises in detected cases, hospitalizations—and, eventually, deaths.

It’s also worth noting that cases in the South are currently declining less rapidly than did cases in the Northeast when full lockdowns were instituted in late March. As a return to widespread lockdowns seems unlikely, we would expect this regional case decline to remain more shallow than the April/May drop-off that ended the first surge of COVID-19 cases in the United States. 

A decrease in diagnosed cases of COVID-19 paired with increased testing is an encouraging indicator for the next few weeks—but the level of community transmission remains high. As we saw in late May, these trends can be reversed very quickly.

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