Trends Improve Except in the Midwest: This Week in COVID-19 Data, Sep 24

This week in US COVID-19 data

As fall began and the US death toll from COVID-19 approached 200,000, the weekly data showed some positive trends. Testing continued to rise—up 14 percent from last week, though perhaps with some caveats; hospitalizations continued to decline, and deaths were down 15.1 percent. This week 5,110 people died of COVID-19 in the US; the seven-day average death toll has remained under 1,000 since August 22.

This week many COVID trackers reported that the United States passed a depressing benchmark: 200,000 deaths caused by the virus. The COVID Tracking Project’s figures, meanwhile, remain just below this level. We explained why this divergence exists—it’s due in large part to differences in how New York City and New York State report probable and confirmed deaths—but the gap illustrates how difficult it is to arrive at a consensus when measuring the pandemic’s impact.

Testing on the rise, but lacks clarity

On September 19, more than 1 million COVID-19 tests were conducted in the US—the highest number in a single day on record. As testing figures continue to rise, though, a number of states are lumping the results of newly-available antigen tests with the results of the gold-standard PCR tests. 

As we explained last week, antigen tests, which are less expensive than PCR tests and provide results more quickly, can help identify people when they are most infectious to others. However, until recently, almost all tests administered in the US were PCR tests. Now, as states are adding antigen testing to their toolboxes, the pipelines in place to track and report PCR tests may not be sufficient to provide the full testing picture. As reported recently by KHN, as many as 21 states do not report all antigen test results, and at least 16 “do not count positive results from antigen tests as COVID-19 cases.”

To be clear, increased antigen testing is a positive development. Since they are cheap and fast, antigen tests are a valuable tool to help reduce transmission in settings like nursing homes, schools, and workplaces. But if the country is conducting hundreds of thousands—or even millions—of antigen tests a week without a way to report results, the public health value of these tests is greatly diminished. Further, when antigen tests and PCR tests are reported lumped together as a single number, the data becomes more difficult to interpret: PCR and antigen tests have very different characteristics, and mixing their results may change the baseline for some metrics. 

The COVID Tracking Project’s national total tests figure does not include separately reported antigen tests, but since some states report a single tests figure that includes both PCR and antigen tests, an unknown number of antigen tests are creeping into the national total. Whenever a state reveals that they are lumping PCR and antigen tests, we note this in the public notes on our main data page, on their state page on our site, and in our API. Ideally, we’d see states report both sets of figures as comprehensively as possible.

The Midwest and the Great Plains

As shown in the graph above, new case counts in the South and West have improved dramatically from the mid-summer. Currently, though test numbers are rising across the country, the Midwest is the only region where cases are seeing sustained growth. This has yet to result in dramatic regional spikes in hospitalizations and deaths similar to those seen in the South and West in prior months.

However, in a few Midwestern and Great Plains states (which fall into the West Census region), the picture is more concerning. Last week we wrote about worrying trends in the Dakotas. This week, though deaths in both North and South Dakota fell, cases and hospitalizations are up. North Dakota saw the highest number of new cases per capita in the country. And while test positivity is a fraught metric—check out our story on the topic here—South Dakota’s is headed in the wrong direction. According to the South Dakota Department of Health, test positivity was 13.3 percent over the previous 7 days, and 16.6 percent on the most recent day.

For nine states, the highest single day for recorded cases since the start of the pandemic happened in the past week. (With one exception, South Carolina, all were in the Midwest and Great Plains.) More testing, including more repeat testing in settings like universities, may mean that an increase in case numbers on its own is a less clear signal than it once was, but record case highs have typically meant more serious outcomes, like increased hospitalizations, are on the way.

The number of hospitalized COVID-19 patients rose in over half of US states this week. Most states saw marginal changes. The largest increases corresponded closely to those states dealing with case surges, again concentrated in the Midwest and Great Plains. Notably, Wisconsin set a new record for the number of hospitalized COVID-19 patients. The state has seen rapid growth in cases among the 18-to-24-year-old demographic, though hospitalizations are most common among the elderly. In other hard-hit states, cases often began to spread among younger demographics before moving into more vulnerable populations.

There remains a mixed COVID-19 picture across the country as autumn gets underway. Decreases in hospitalizations and deaths should be celebrated. But that trend is not universal—worries remain about the Midwest and Great Plains and trends may worsen as colder weather pushes more activities indoors. Transparent, accurate data is needed now more than ever, so we’ll persist in seeking comprehensive reporting of antigen test results. 

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