Data Snapshot: Covid testing now at Spring 2020 levels.

In a multi-pronged approach, you need all the prongs.

Tracking the Covid-19 pandemic has been an evolving process. First we had PCR tests—but not enough of them. Then we had enough, but the results were sometimes too slow in coming to be effective in stopping spread. At-home rapid tests came on the scene which are faster and more actionable, but must be used serially after an exposure (i.e., for several days in a row), lest a person just infected test negative one day, but turn positive (and thus contagious) the next. Finally, coronavirus wastewater levels are useful for tracking surges, but they don’t provide individuals with yes-or-no results that can be acted on.

All told, PCR tests, rapid tests, and wastewater complement one another, helping keep tabs on outbreaks, both at home and in the community.

With the Covid-19 public health emergency officially ending next month, however, fewer people will likely seek out PCR tests; these tests may no longer be free with health insurance, as they mostly are now. That could be a problem at some point.

We decided to look at how many PCR tests are actually being conducted in the US nowadays. Currently, we are averaging around 194,505 tests per day (rolling 7-day average). That’s just 7.3% of the peak of our testing in the US, which happened at the beginning of January 2022 (in the early days of the Omicron surge). At that time, we were doing 2,635,629 tests per day in the United States.

We’re now doing about as many PCR tests per day as we were back in May of 2020.

Testing winners and losers.

Interestingly, there are handful of states still doing more than 10% of their 2022 PCR testing maximums.

In particular, South Dakota and Alabama are at 13% of their all-time testing highs. But there’s a catch. These two states had the lowest peaks of any of the 50 states (plus DC). They’re the closest to their all-time testing highs because they didn’t have that far to fall. Meanwhile, many of the states which tested the most during surges have now fallen further (i.e., are at lower percentages of their own maximums).

In the future, I suspect that wastewater spikes will trigger an increase in PCR and rapid Covid-19 testing. Getting the balance right—between wastewater, PCR testing, and rapid test dissemination—will be an ongoing challenge in the years to come. The key will be to maintain testing capacity so that we can respond to crucial wastewater data soon enough to stop outbreaks early. In a multi-pronged approach, you need all the prongs.

Final thoughts.

Covid-19 is not the only viral threat at this stage. We need wastewater, lab-based, and at-home tests for a variety of pathogens. If the remainder of this century is to “go well,” we’ll need to shore up the right surveillance portfolio and have a number of plans in place. Few places, if any, are as ready as they could be.

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Thanks to Benjy Renton for curating Data Snapshot.

Data source: https://healthdata.gov/dataset/COVID-19-Diagnostic-Laboratory-Testing-PCR-Testing/j8mb-icvb