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Monday, February 26, 2024

The US Is Disastrously Behind in Coronavirus Testing. Again

In most places in America, it’s not hard to get a Covid-19 test right now. You can walk into a clinic, pharmacy, even your local Wal-Mart, and walk out again, nose swabbed, without too much trouble. Getting the results of your test, on the other hand … well, let’s just say you should be prepared to wait. And wait.

This is a largely different problem than the testing woes that plagued America’s pandemic response in the early months of March and April. Back then, supply shortages, faulty test kits, and federal regulations limiting testing to only certain kinds of labs hindered widespread availability of tests.

Since then, diagnostics manufacturers have significantly boosted production of the materials required to conduct Covid-19 tests. The federal government moved to require that Covid-19 testing be covered by both public and private insurers. Laboratories dramatically ramped up capacity. Today, the US tests 174 people out of every 100,000, second only to Hong Kong in per capita testing. According to the Covid Tracking Project, the US is testing about 725,000 people per day, up from about 640,000 a month ago.

But as a surge in Covid-19 cases intensified across the southern and western US in June and July, demand for tests soared, and the nation’s testing infrastructure buckled. Backlogs at commercial labs left people in some states waiting a week or more to receive results. While the situation is starting to improve, many Americans are still experiencing significant delays. And the longer a potentially contagious person is forced to wait for test results, the higher the likelihood they’ll unwittingly infect others, potentially setting off new outbreaks and making it much harder for public health agencies to slow the spread of the virus.

According to a new nationwide survey, conducted by a consortium of researchers at Rutgers, Northeastern, Northwestern, and Harvard universities, most people are not getting results within the 24- to 48-hour window recommended by public health experts to aid effective contact tracing. And about 20 percent of those tested, many of them Black and Latinx, are being forced to wait more than five days for test results, effectively rendering them useless. Overall, about 10 percent of surveyed people reported waiting 10 days or more.

“If you’re waiting 10 days or more, you can just throw those results out. They’re not helping anyone,” says Katherine Ognyanova, a network scientist at Rutgers University, and one of the coauthors of the report, which was released Monday. Every week, she and her colleagues push out an online survey to tens of thousands of Americans, distributed across every state and the District of Columbia. They were hearing stories and reading news reports about people waiting weeks to get results, but they couldn’t find any systematically collected data on testing turnaround times.

That’s because Covid-19 tests are conducted by a number of different, disparate entities—including hospitals, public health labs, big commercial labs, and academic centers. How long someone has to wait for test results is determined by a number of factors, including where their swab is processed, what kind of demand that facility is facing, and a sorting process that prioritizes certain people—health care workers, hospital patients, known contacts of confirmed cases—into a testing fast lane.

“States are tracking a lot of testing data, but wait times are not something that any of them are reporting,” says David Lazer, a computational social scientist at Northeastern University and coauthor of the report. He and his collaborators hoped to use their online questionnaire to provide a snapshot of what Americans are experiencing on the ground.

The researchers found that of the 19,000 people surveyed, about 18 percent of respondents had been tested for the virus. Of those, only 37 percent received results within 48 hours. People tested in July reported an average wait time of about four days, about the same as those who reported taking a test in April. Overall, the national average was three days, with people in virus hot spots like Arizona, California, Florida, and Texas waiting on average four or five days.

The survey also revealed racial disparities. Black people reported an average wait of five days, and Latinx respondents reported waiting 4.6 days on average, compared with 3.9 days for white people. The results align with a recent investigation by NBC and FiveThirtyEight, which found that testing sites in communities of color in many major cities face higher demand and experience worse staffing shortages than whiter or wealthier areas in those same cities. Which means that the people disproportionately suffering from Covid-19 are less likely to get timely test results.

“The national average might not be as high as we feared, but it’s not comforting when it still means that half of people who get tested are waiting longer than three days, and the people waiting longest are in the communities that are hit hardest by this disease,” says Ognyanova. “Fixing testing times cannot be done piecemeal, because we’re all interconnected. As long as some of these communities are having these issues, the rest of the country is not safe.”

Testing is just the first step in a three-part strategy that many countries in Asia and Europe have used effectively to contain the coronavirus. The next two are contact tracing—identifying people who’ve come in contact with known cases—and isolating those people for 14 days so they don’t pass an infection on to anyone else. Because the virus takes an average of five days to incubate inside a person, replicating enough copies of itself to make the host, if not sick, then at least infectious, it’s crucial to reach those contacts as quickly as possible. Testing delays make that much harder.

“It’s pretty demoralizing when cases aren’t timely reported, and we’re not able to reach people as quickly as we need to,” says Mike Reid, an assistant professor of medicine at UC San Francisco who has been working with the San Francisco Department of Public Health to help train the city’s rapidly expanding contact-tracing workforce. From 60 contact tracers in April, Reid says they now have 130 on the job, with another 50 being onboarded this week. He says the city’s rapid uptick in cases in June and July took them by surprise. According to data collected by city officials, the public health department was reaching about 89 percent of confirmed cases in early June. By the end of July, they were only reaching about 75 percent. “We just weren’t able to stay on top of cases as well,” says Reid.

Contact tracing fared a little better, in part, says Reid, because the department now moves any named contacts to the front of the testing line. Every day, city staff set aside a quota of tests available just for people who’ve been named as close contacts of confirmed cases. On average, says Reid, those people are able to get scheduled within 24 hours. They won’t face the same delays as the general public. But it’s not clear if anything like this is happening nationwide. “I’d be surprised if we’re the only ones doing that,” says Reid. “But is it common practice? I can’t say for sure.”

Timely test results are essential not just for contact tracing but also for understanding what’s going on with transmission, says Emily Gurley, an infectious disease epidemiologist at Johns Hopkins Bloomberg School of Public Health. There is already a lag between when someone gets infected and when they develop symptoms—if they develop symptoms at all, which many don’t. And there’s also a lag between when someone gets sick and when a sample is collected from inside their nose. If it takes a week to get results back, it’s likely that person was infected at least two weeks ago, maybe three. “That means we’re always behind the curve and don’t know what’s happening right now,” says Gurley. “It’s been just incredibly frustrating to see these sorts of delays again.”

Local reports of long testing times began to emerge in early July, in states like Arizona and Texas. By the end of the month, officials at Quest Diagnostics, one of the country’s largest commercial medical-testing laboratories, sent out a media update that said the company’s systems were overloaded. As a result, they wrote, they were prioritizing a 24-hour turnaround time for hospitalized patients, those facing emergency surgery, and sick health care workers. Everyone else could expect to wait seven or more days.

Commercial labs like Quest and its largest competitor, LabCorp, are responsible for approximately half of the Covid-19 testing in the US. Hospitals, public health laboratories, and point-of-care diagnostics make up the rest of it. Many of them were similarly overwhelmed. In mid-July, the American Clinical Laboratory Association put out a statement that many of its labs were receiving more tests than they could process. Eric Blank, the chief program officer for the Association of Public Health Laboratories, told WIRED that the issue now is shortages not of testing kits, but of the 30 or so other things required to run a test—including pipettes, plastic tubes, and personnel.

“You’ve got labs doing a lot of Covid-19 testing and all looking for the same supplies, and these supply chains weren’t built to fill these big surges in demand,” says Blank. But the bigger problem, at least for public health labs, which often handle state-funded testing drives at nursing homes, prisons, and community sites, is not having enough hands. Staff who were commandeered from other departments in the early days have been sent back to their regular jobs monitoring water or testing for foodborne illnesses. “It was all hands on deck, but we can’t rely on those staffers anymore” says Blank. “And the demand has only been growing.”

To meet this demand, the Department of Health and Human Services has started standing up temporary federal surge testing sites in Covid-19 hot spots like Baton Rouge, Bakersfield, and Miami, according to an HHS spokesperson. The agency also plans to send 2,400 point-of-care testing machines to nursing homes throughout the nation to free up lab capacity elsewhere. Additionally, the Food and Drug Administration awarded emergency use authorizations to Quest and LabCorp to start testing pooled samples. This testing format would allow for multiple samples to be mixed together and tested at the same time, a way of streamlining the process and conserving supplies like reagents. If all samples test negative, everyone in the pool can be cleared simultaneously. If the pool tests positive, then individual samples will be analyzed to identify the infected person.

On Monday, Quest released a statement saying the company had implemented pooled testing at three of its laboratories, which had helped increase capacity from 135,000 tests per day to 150,000. Even so, the statement continued, the company expects this to be the third consecutive week of lab capacity being outpaced by demand. And as a result, the average turnaround time for its priority patients is now two days, with five days for everyone else.

Some testing experts are skeptical that sample pooling will actually cut wait times. The technique is generally recommended for use in populations where prevalence of the disease is quite low. And in many parts of the US right now, transmission rates are just too high. “If the idea is to make the reagents last longer and help with reducing the backlog, but every time you test a pool you get a positive result, you have to retest all those specimens,” says Blank. In other words, the efficiencies evaporate. “Pooling can be helpful, but it really has to be used in the right situation,” he continues.

According to a Quest spokesperson, the company is conducting pooled testing at its labs in Marlborough, Massachusetts; Chantilly, Virginia; and San Juan Capistrano, California. “It is true that specimen pooling is not appropriate in areas where there are high prevalence rates,” she wrote to WIRED in an email. However, she added, by freeing up capacity in labs in these regions, where prevalence is quite low, Quest can shuttle in specimens from harder-hit labs to increase turnaround times. At those three facilities, Quest is able to run four samples at a time, but data on what percentage of those pools turn up positive hits is unavailable at this time, according to the spokesperson.

As frustrations with the nationwide testing backlogs boil over, some policymakers are pushing for more creative solutions. On Tuesday, the governors of six states signed an agreement to work together with the Rockefeller Foundation and two rapid-test manufacturers to bring 3 million tests to the people in their states: Louisiana, Maryland, Massachusetts, Michigan, Ohio, and Virginia. Unlike the PCR tests that can take hours to detect viral genetic material in a sample, these tests, produced by Quidel Corporation and Becton, Dickinson & Company, measure fragments of the virus itself. The process delivers results in 15 to 20 minutes, but the rates of false negatives are much higher.

The White House’s testing czar, Admiral Brett Giroir, told CNN on Sunday that the US is “completing over 80 percent of our tests within three days, almost 90 percent within five days.” But as far as getting wait times down to just two days? He testified to Congress Friday that that “is not a possible benchmark we can achieve today.”

The way epidemiologists like Emily Gurley see it, improving testing is necessary, but not sufficient for controlling a virus that is still killing more than a thousand Americans every day. Testing is one part of the equation. Contact tracing is another, and so are masks and physical distancing and improved ventilation. But curbing the spread really all comes down to limiting the number of susceptible people an infectious person can come into contact with, she says. “If we want to do that, we’ve got to be serious about throwing everything at it,” she says. “And I don’t think we’re serious about throwing everything at it in most parts of the country.”

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