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America’s coronavirus testing numbers are really improving — finally

The US still has work to do, but it’s on a positive trend.

Health care workers wait for patients to be tested at a walk-in coronavirus testing site in Arlington, Virginia, on May 12.
Olivier Douliery/AFP via Getty Images

After an April that some experts described as “wasted,” it looks like America is finally making some real progress on coronavirus testing in May.

Over the past couple of weeks, the United States has seen significant improvements not just with the raw number of Covid-19 tests but also with other metrics experts use to gauge the scope of the US’s coronavirus outbreak and its testing capacity.

During the week of May 5, the US averaged nearly 300,000 new coronavirus tests a day, according to the Covid Tracking Project. That’s nearly double the roughly 150,000 daily tests performed in early April, although it still falls short of the number of new tests a day experts say is needed to fully control the outbreak — a number that ranges from 500,000 on the low end to tens of millions on the high end, depending on which plan you’re reading.

Testing for coronavirus has passed 350,000 tests per day.

The US also saw a significant improvement in another key metric for coronavirus testing: the positive rate, or the percentage of tests that come back positive for Covid-19. Generally, a higher positive rate suggests there’s not enough testing happening: It indicates only people with obvious symptoms are getting tested.

The US’s positive rate over the week of May 5 was nearly 8 percent — down from almost 21 percent the week of April 5. Experts have said the positive rate should be no higher than 10 percent, but preferably much lower.

“Daily [Covid-19] testing continues to increase nationally while the positivity rate continues to decline,” Scott Gottlieb, former head of the Food and Drug Administration, tweeted. “These are hopeful signs that — at least in many parts of the nation — the epidemic is slowing.”

This doesn’t, however, mean the whole country is ready to start reopening the economy just yet. Even the latest numbers, as promising as they are, fall short of what some experts have called for. And by other metrics, the US is still behind where it needs to be.

It’s also unclear if the gains will hold and continue. There were significant improvements in testing for much of March, only for those gains to stop in April. Future problems with testing could slow more increases.

But, at least for now, America has — finally — made some real progress.

Testing is getting there, according to a key metric

Testing is crucial to controlling the coronavirus pandemic. Paired with contact tracing, testing lets officials track the scale of an outbreak, isolate the sick, quarantine those with whom the sick came in contact, and deploy community-wide efforts as necessary. Aggressive testing and tracing are how other countries, including South Korea and Germany, got their outbreaks under control, letting them start reopening in the past couple of weeks (though even they have scaled back their reopenings after new spikes in Covid-19 cases).

That Covid-19 tests are increasing while the positive rate is falling indicates the US is now moving toward enough testing capacity to match the scope of its outbreak.

Some of the drop in the positive rate is likely the result of improvements in New York state, which had the worst Covid-19 outbreak in the US so far. New York state’s positive rate peaked above 50 percent in late March and early April, before falling to around 9 percent in the week of May 5.

New York’s positive test rate reached 50 percent in April, but has dropped to around 10 percent. The US rate did not rise as high but has also dropped.

Even excluding New York, though, the US’s positive rate has also dropped: from around 17 percent in mid-April to nearly 8 percent the week of May 5.

A majority of states now have coronavirus positive rates below 10 percent, which experts say is the acceptable maximum. Only 15 states and Washington, DC, had a positive rate above 10 percent during the week of May 5.

A state-by-state map of coronavirus testing positive rates.

The US is still far from where some other countries are on testing. According to Our World in Data, New Zealand, Taiwan, and South Korea — all places that have done a better job controlling their Covid-19 outbreaks — have positive test rates below 2 percent and even 1 percent.

“‘Test, test, test’ means numbers more in that low range,” Natalie Dean, a biostatistics professor at the University of Florida, told me. She added, “We need a lot more testing.”

Much of the progress so far is despite a lack of federal leadership. Over much of April, testing numbers stagnated due to supply shortages for swabs, reagents, and other materials needed to collect samples and run coronavirus tests.

Experts have said that the federal government, led by President Donald Trump, should lead national efforts to boost testing. But Trump’s “blueprint” for testing explicitly leaves the problem to the states and private sector, saying the federal government will only act as a “supplier of last resort.”

Most states need more time before they can safely reopen

Despite the improvements, experts caution that the US shouldn’t rush to fully reopen its economy just yet.

The White House’s guidelines and experts’ proposals lay out which standards states have to meet to reopen — letting each of them slowly reopen with a phased approach that unlocks parts of the economy bit by bit. For that phased reopening to begin, the proposals typically call for decreases in new Covid-19 cases for two weeks and enough testing to diagnose all of the sick and their contacts.

Most states don’t meet either standard.

With testing, most states now fall below the 10 percent positive rate. But when it comes to reaching the positive rate seen in, say, South Korea or New Zealand, just six states — Alaska, Hawaii, Montana, Vermont, West Virginia, and Wyoming — have rates below 2 percent over the week of May 5.

Testing also has to be paired with contact tracing, in which “disease detectives” track down who the infected came in contact with and get those contacts to quarantine. Experts have called for the US to hire between 100,000 to 300,000 contact tracers. Based on a tally kept by NPR, 44 states and Washington, DC, plan to hire about 66,000 contact tracers as of May 7 — almost two-thirds of the minimum.

With overall cases, the country as a whole has seen its daily new reported Covid-19 cases drop in May. But much of that decrease originated in Connecticut, New Jersey, and New York — the three states included in the New York City metro area, which suffered the worst outbreak. When those three states are excluded, the US has seen daily new Covid-19 cases at best start to drop only in recent days — far from the two weeks of decreases that experts recommend.

A chart of America’s diverging coronavirus epidemics. German Lopez/Vox

Some of the upward trend in Covid-19 cases outside Connecticut, New Jersey, and New York in recent weeks is likely due to increased testing. Even though fewer tests are coming back positive, doing many more tests can still mean finding many more cases than a state would otherwise.

Still, the numbers suggest it’s too early to declare victory. Based on data compiled by the New York Times, just 18 states have seen their daily new reported coronavirus cases drop in recent days — much less the two full weeks experts have called for. Seven states have seen their daily new cases increase, while the remaining 25 have seen theirs remain roughly flat.

Taken together, these figures suggest that the majority of states are not ready to start to reopen just yet. While America has made decent progress throughout May in confronting the challenge of this pandemic, there’s still a bit more work to be done.

Correction: The positive rate map originally had incorrect data for Utah and Virginia due to a bug in the map-making program. It’s been fixed.

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