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Why can’t America fix its Covid-19 testing problems?

US testing numbers have been consistently bad because there is no real strategy.

A health care worker in full mask, gown, gloves, and face shield performs a Covid-19 test swab outdoors on a student heading to school.
With the delta variant surging, the US is not performing enough Covid-19 tests to adequately surveil the virus.
Brianna Soukup/Portland Press Herald via Getty Images
Dylan Scott covers health care for Vox. He has reported on health policy for more than 10 years, writing for Governing magazine, Talking Points Memo and STAT before joining Vox in 2017.

A year and a half after the Covid-19 pandemic began, the United States is facing a new version of the same problem that stymied its response from the beginning: We aren’t testing enough to catch every case or surveil the virus and its new variants.

Nationwide, about 11 percent of tests are now coming back positive, according to Johns Hopkins’s testing data, up from 2 percent in mid-June. Experts have said the positive test rate should be below 10 percent and preferably much lower in order to be confident most cases are being caught. In some of the worst hot spots across the US, test positivity is even worse — about 20 percent in Georgia and Kentucky, for example. At the local level, some counties in Florida are seeing as many as 40 percent of tests come back positive.

The number of tests performed daily has grown considerably over the summer, in parallel with the delta surge, from a daily average of about 450,000 in early July to about 1.5 million at the end of August. But the US still isn’t doing enough.

The current numbers suggest that more tests are being performed because more people are feeling sick and getting tested — but that a lot of cases are still being missed, either because a person never feels symptoms and doesn’t get tested, or because they can’t access a test even when they do have symptoms.

Earlier this summer, when the pandemic seemed to ease, testing capacity also diminished — testing sites closed, rapid testing kits were discarded — leaving the country rushing to ramp up surveillance over the past month when the delta variant sent case numbers soaring.

The US lost testing capacity at a critical juncture in the pandemic, which has constrained its ability to surveil the virus. According to data compiled in Arizona State University professor Mara Aspinall’s newsletter on Covid-19 testing, America’s capacity actually fell from July to August, from 409 million tests to 403 million, the first time that a decrease had occurred in at least a year. Anecdotal reports abound of Americans struggling to find a test right now.

The nation’s testing problems, according to several experts I spoke to, start with its failure to establish a clear goal for Covid-19 testing. Are tests meant to clinically diagnose specific patients to guide their treatment? Is the goal monitoring the virus broadly, to determine exactly how widespread it is across the whole country? Or is it to identify positive cases so the people who test will isolate and avoid transmitting the virus to other people?

Some experts think the last option — screen and isolate — would have been the most promising. Countries like South Korea excelled in crushing Covid-19 during the early weeks of the pandemic with a similar strategy. But the US has never come close to testing enough to make that happen.

“Insufficient testing is a prime candidate for the biggest missed opportunity in public health throughout the pandemic in the US,” Josh Michaud, associate director of global health policy at the Kaiser Family Foundation, said in an email. “It was a missed opportunity at the start of the pandemic, and remains a missed opportunity even now.”

Now, with delta surging, the US does not have enough tests available to adequately surveil the virus.

“We’re gonna need everything,” Paul Romer, a Nobel Prize-winning economist who has argued since last year for more robust testing, told me over the phone. “It’s really an amazing and profound tragedy that we’re not using screen and isolate as a way to get to the goal of reducing the spread of the virus with fewer restrictions.”

But America, first because President Trump actively deterred more testing and then because the country prematurely declared victory over the virus when cases waned earlier this summer, never settled on the objective for testing and still hasn’t — 18 months into the pandemic.

The real reason America’s Covid-19 testing has been so consistently bad

The testing problem isn’t just with the tests themselves. It’s that the US never figured out what to do next.

Rapid antigen tests that return results in a matter of hours have been on the market for a year. But the United States has never embraced their full potential to support a “screen and isolate” program.

“Rapid antigen testing has been a severely underutilized public health tool,” Michaud said. “A public health-forward approach would call for lots of rapid testing of lots of people.”

It has been done. The United Kingdom announced in April it would make Covid-19 tests available twice a week to anybody who wanted them. Germany has also been relying on widespread rapid testing to ease back into normal life with fewer restrictions while also surveilling for new clusters.

The UK in particular is dramatically outpacing the US in the number of daily tests performed per capita. Israel, which also ramped up rapid testing when delta surged, was performing five times as many tests per capita as the US, as of last week. Germany, meanwhile, is dealing with substantially fewer cases per capita than the US is, about one-fifth as many currently.

The argument against overrelying on rapid antigen testing is that those tests are not as accurate as the diagnostic PCR tests that take longer to process. But some experts argue a few healthy people isolating because of a false positive result would be preferable to having everybody isolate under stay-at-home orders or, on the other end of the spectrum, allowing the virus to escape detection because of insufficient testing.

“It’s unambiguous. Any screening and isolating reduces the total restrictions you put on people,” Romer said.

Missing asymptomatic cases has always been a problem for the United States because the country has never instituted population-level testing. People usually only get tested if they feel sick and go to the doctor or a testing site (or, more recently, order an at-home test).

But without sufficient testing, public health officials have a harder time tracking the coronavirus’s spread. The delta variant is more contagious than the previous versions of the virus, and, like previous iterations of the virus, it’s possible that even people with mild or no symptoms can spread it to others.

If those people got tested and knew they were infected, they could try to self-isolate and avoid contact with other people. But if they don’t, the virus can spread silently. That’s why experts like Romer have been urging the United States to test more since the beginning of the pandemic, specifically pooled testing of the general population, which includes people who don’t feel any symptoms.

But it’s never happened — in part because of early struggles to increase America’s testing capacity, in part because testing was not a priority for the Trump administration, and in part because the United States took a premature victory lap over Covid-19 earlier this summer and let its guard down.

The US picked the worst time to have more Covid-19 testing problems

The testing problems in the US go back to the beginning of the pandemic. The development of testing kits was centralized at the Centers for Disease Control and Prevention, and the kits initially sent out by the agency were flawed. America trailed badly behind countries like South Korea that quickly set up a testing program. The US lost track of a new virus that was soon spreading in every corner of the country.

Even as capacity increased, testing was hamstrung by a reluctant federal government. Though Congress appropriated millions upon millions of dollars for testing, Trump said he actually hoped fewer tests would be conducted — because that would mean fewer cases would be identified and recorded. The Trump administration kept testing guidance more limited than outside experts said it should, never embracing testing asymptomatic people as “screen and isolate” would require.

But the latest errors were perhaps the most easily avoidable. Cases dipped in the late spring and summer; the CDC started relaxing its masking guidance in May, and President Joe Biden told the American public life would be relatively normal by July 4.

That false sense of security led to mistakes that would leave the nation struggling to catch up when the delta variant took over.

As the New York Times reported recently, Abbott Laboratories over the summer had employees destroy its rapid testing kits and throw them away because demand for tests had slacked so much. Workers were laid off, and one of the major plants was closed. The company has been scrambling to ramp back up its manufacturing and hire back workers now that testing demand is rising again. Aspinall’s newsletter called it “a classic example of unforced error.”

Florida closed some of its publicly run testing sites in May, when its case numbers were lower, and hasn’t reopened them despite the current surge. Employers, K-12 schools, and universities have generally been reluctant to embrace rapid testing, Michaud said. Kaiser Health News explained the many troubles encountered by Missouri schools trying to set up more robust testing regimens, ranging from pure logistics to concerns about the risk of healthy people having to isolate to some of the generalized backlash faced by schools all over the country that have sought to be more proactive with their Covid-19 protocols.

All of those mistakes combined to leave the US ill-prepared to track the virus when delta sent cases soaring again in July.

“Instead of keeping surge capacity ready to go in case of another surge, suppliers and jurisdictions doing the testing cut back prior to the emergence of delta,” Michaud said, “which meant systems were often caught flat-footed when cases started surging again.”

The expansion of at-home rapid testing should help increase the number of tests available. Aspinall’s newsletter projects testing capacity will rise to 672 million by December 2021.

But it may be too little, too late — again. The United States is currently averaging 150,000 new cases every day, making this the second-worst wave of the pandemic. Those are only the cases we can actually count, because somebody got a test. What we don’t know, and what we may never know, is how many infections are being missed.