Top news, reports and insights for today:
I wish to thank those who reached out to me in the past few days with encouragement and feedback. I needed to hear that my efforts in this blog are making a difference. My plan is to continue with regular briefings at least 3 times a week (tentatively Tuesday, Friday and Sunday). I will add supplemental posts when timely and important events arise. I plan to add a new feature: reader comments and questions. I will add an option on the blog for visitors to post specific questions of interest. I will try to address those questions as best I can and share the back and forth in this space. Thanks again for continuing to read this blog and I look forward to continuing to bring you fair, balanced and scientifically-oriented news, insights and analysis. Please keep the feedback coming!
- Daily headline summaries for Tuesday:
- U.S. coronavirus deaths top 150,000 (NBC News)
- It’s not just the U.S. that is experiencing coronavirus fatigue as several European nations are seeing recent spikes in new cases as control measures become more lax (Washington Post)
- At least a dozen states are running out of doctors and nurses as COVID-19 cases surge. Shortages are especially acute in intensive care units. Military units stepping in to assist in California (ARS TECHNICA)
- Opinion from 19 doctors and a nurse: Trump administration issued a new rule this month requiring hospitals to report COVID-19 data directly to the Trump administration instead of the CDC. “This sudden and radical decision to change hospital reporting from the CDC to a private third party within the Department of Health and Human Services will disrupt established lines of communication and has grave potential to hobble our ability to respond to the pandemic….” (USA Today)
- U.S. daily cases have leveled out; the latest half million cases added in just 7 days
From Mid-June till Mid-July, we have seen daily cases rapidly and steadily rise in the U.S. as a result of widespread transmission intensity across multiple states and regions. In the last week, that trend has finally shifted and new COVID-19 cases have plateaued. That is welcome news. As was the case in the first apparent peak in late April, it is not clear if the flattening is driven by the epidemic itself or by a new ceiling in testing capacity. There is evidence that both are at play (see main point 3). The U.S. now has over 4.2 million total lab-confirmed COVID-19 cases, which is over 1/4 of the world’s cases (27%). The cumulative total rose from 3.5 to 4 million in just 7 days, the shortest interval thus far that half a million cases were added (See Figure B).
At the state level, transmission intensity remains high in many states. Two states now exceed the overall rates of infection per 100,000 in New York (now at 2,120 per 100,000): Arizona (2,251) and Louisiana (2,394). New daily cases over the last week per 100,000 is shown in Figure C. Fourteen states added 25 or more new cases per day last week including Arizona (+37), California (+25), Idaho (+27), Nevada (+33), Oklahoma (+26), Alabama (+33), Arkansas (+26), Florida (+48), Georgia (+34), Louisiana (+46), Mississippi (+44), South Carolina (+30), Tennessee (+35), and Texas (+26). Transmission continues to be well controlled in much of the Northeast where Connecticut, Massachussetts, Maryland, Maine, New Hampshire, New York, New Jersey and Vermont remain below the benchmark value of 5 new cases per day per 100,000.
The bottom line: The overall trend is flattening of new cases. It is possible we have simply maxed out on testing capacity. The virus continues to spread extensively in 14 states. Conditions in Arizona, Nevada, Alabama, Florida Georgia, Louisiana, Mississippi and Texas remain especially alarming.
- What’s going on with testing in the U.S.?
Across the nation, testing is under the microscope. Viral twitter posts have planted the idea that the U.S. only thinks it’s in bad shape because we are testing too many people. More tests make more cases, so the logic goes. Some national leaders have suggested a slow down in testing. The Trump administration has sent mixed signals. This week, “Uncle Toni” Fauci, the nation’s top infectious disease doctor told government panels two key things: 1) more testing does not lead to more cases by itself, and 2) he has never been told by the White House to slow down testing. But the question remains in a lot of minds: is the recent surge in cases just about more testing?
To begin tackling this, let’s consider some basic facts. First, it is true that relative to the true underlying rate of a disease, the more testing that is done, the higher will be the number of cases identified. That’s why we have to look beyond total numbers of positive tests. Second, just as with cases, we can be easily mislead by looking at the raw number of tests. We have to look at rates. There are two that matter. The first is tests per million people. There are now 78 countries with 10,000 or more cases. Among those nations, the U.S. currently ranks 1st in total cases and 9th in testing per 1 million. That’s an improvement since the U.S. ranked 17th 2 months ago. The top graph below is from OurWorldInData.org and shows the current place of the U.S. in testing rate compared to some other key nations. It shows we are in the middle of the pack. It also shows that while testing rates have climbed steadily, there is no big jump that would explain the June surge in cases.
The other key rate is the test positivity rate (TPR). In many ways, the TPR can be a better measure of viral transmission intensity than the number of positive tests. Ideally, we would like the TPR to be at or below 5%, which tells us we are testing broadly in the population and that 95% of people are testing negative. In the early phase of the epidemic, we are only testing selectively: mostly those we already know to be sick. For that reason, the TPR was over 30% in the initial weeks of the pandemic. Let’s look now at the lower graph I made using data from the COVID Tracking Project, showing total tests per day in the U.S. and TPR since May 1. This graph shows two really important things. The blue bars are how many tests we are doing a day. That number has been steadily climbing since May 1. But, and here is the important point, it appears the growth in testing has flattened in the last week and may be declining. That is important when we put the numbers of daily positive tests in perspective. It is possible that the flattening of new cases is partly due to a flattening in the growth of new tests. To help clarify, we look at the orange line, which shows the TPR. That number fell from 17% on May 1 to around 8% in late June. Total tests continued to rise, but TPR did not fall. That’s important. If it had, we would be able to say that our testing is coming into better alignment with the true magnitude of the outbreak. That didn’t happen. The TPR has been consistent since Mid-June. That’s a sign that the surge in cases is mostly about the epidemic, and not “excess testing” whatever that might mean.
The bottom line: We still aren’t testing enough. The surge in cases is mostly the spread of disease, not the rise in testing. Our capacity to test may have maxed out, suggesting we should be cautious in celebrating the apparent plateau in cases.
Thomas A. Glass, Ph.D. 