In the aftermath of a 2015 outbreak of the Middle East Respiratory Syndrome that killed 38 people and cratered the economy, South Korea took a hard look at what had gone wrong. Among the findings: A lack of tests had prompted people ill with the disease to traipse from hospital to hospital in search of confirmation that they had MERS, a coronavirus far more virulent than the one that causes COVID-19. Nearly half the people who got the disease were exposed at hospitals.

Korean officials enacted a key reform, allowing the government to give near-instantaneous approval to testing systems in an emergency. Within weeks of the current outbreak in Wuhan, China, four Korean companies had manufactured tests from a World Health Organization recipe and, as a result, the country quickly had a system that could assess 10,000 people a day.

Korea set up drive-through test stations, an approach only now being launched in the United States. Health officials initially focused their efforts on members of a secretive megachurch in Daegu with a branch in Wuhan, but they then broadened their reach to Seoul and other major cities. As of Saturday, South Korea had tested more than 248,000 people and identified 8,086 cases.

So far, 72 have died, or 0.9 percent of those infected. Compare that with the Chinese province of Hubei, where the coronavirus first emerged. With no forewarning, the fatality rate for the province currently stands at about 4.5 percent.

The contrast to the United States, which tested a few thousand people in the weeks when health experts say the outbreak was spreading across this country, could not be more stark. Instead of using the template approved by the World Health Organization, the Centers for Disease Control and Prevention set out to create its own test from scratch, only to see that effort plagued by delay and dysfunction that continues to this day.

America’s inability to know who is infected has broad implications. It means that infected people have wandered through offices, buses, restaurants, emergency rooms and malls, indiscriminately spreading the virus.

Testing vs. Not Testing

Gye Cheol Kwon, the chairman of the Korean Society for Laboratory Medicine, said South Korea’s experiences during the 2015 outbreak prompted the creation of a system for “timely and practical use of unapproved diagnostic products when there were no approved diagnostic tests.”

“With our past experience with MERS,” he wrote in an email, “we found it very important to diagnose people quickly and to prevent spread to the community through isolation of infected people.”

The quick fielding of a widely available test gave South Korea a key advantage in fighting the spread of the disease, said Dr. William Schaffner, a professor of preventive medicine and infectious diseases at Vanderbilt University Medical Center. “They used the WHO test, so they had a test that was validated early on. Then, they made a simple decision: Test as many people as possible. They organized themselves to get specimens and then made sure they had a very high throughput in the labs.”

He added, “This was crucial to figuring out where the infection was and where it was not, and then they used this knowledge to direct their public health efforts.”

What they did with that data, to contain the disease, could inform a science fiction movie. Beginning in February, the government posted the precise movements (without names) of everyone who tested positive — everything from the seat numbers they occupied in movie theaters to the restaurants where they stopped for lunch. The government obtained the information from cellphone records, credit card receipts and other private data it is authorized to collect in a health emergency. Other Asian democracies have taken comparably intrusive steps in the name of public health. Hong Kong has tracked some high-risk people under quarantine with wristbands.

Kwon acknowledged in his email that the posting of the information was a “double edged sword” that raised public anxiety about where they could safely go. “However, we believed that if the government did not post extensive details about infected people on social media, COVID-19 would have spread even more quickly.”

In America, the CDC initially set the parameters of who could be tested narrowly, reflecting the scarcity of the test kits. The rules limited testing to people who had been to countries with known hot spots, even while epidemiologists warned that such restrictive criteria would mean missing early detection of cases in which the virus was spread among people with no links to travelers. This limitation appears to have given the disease a head start in some communities, notably Seattle. Then, even when criteria were loosened, the ongoing lack of testing capacity meant that the disease continued to spread, untracked.

ProPublica reporters have heard from dozens of people, throughout the course of the crisis, who could not get a test despite having some or all of the symptoms of the novel coronavirus: fevers, coughs and such a hard time breathing they went to the hospital.

Among them was Caryl Helsel, 55, who returned to New York from a trip to Seattle. She developed a cough and then a fever of 104 with an “excruciating, painful headache” that felt like none she’d ever had. “I thought I was going to die,” Helsel said. She called her doctor’s office on March 5 and said she’d spent time at a Seattle Starbucks where a worker had tested positive. She was told she didn’t meet the testing criteria, since she hadn’t traveled out of the country or been in contact with someone suspected of having the coronavirus.

She was told that despite the “existing pockets” of cases in the U.S., Seattle wasn’t deemed a high-risk area. By this point, the virus was consuming Seattle and its suburbs. Officials didn’t — and still don’t — know the full extent of the outbreak, because not everyone there who is sick is being tested.

Kevin Sullivan, 41, lives just outside of Kirkland, Washington, where the virus tore through the Life Care Center nursing home, killing 22 people as of Friday. He was turned down for testing twice despite developing a “low grade” fever, dry cough and trouble breathing. The first time, he was told by his primary care practice that there were no tests available. “Excuse my language, but ‘what the fuck?’ was kind of my response.” He later called a local hospital, but was told that his symptoms weren’t severe enough to merit a test, and that the most he could expect from a visit was an inhaler.

Doctors who have suspected that people had COVID-19 say they have been unable to test them for it. “Throughout the country, the No. 1 issue is getting tests, because only the CDC and the Department of Health could test. So we had to call them, and they would say no,” said Dr. Celine Thum, who works at a busy trauma hospital in New York City.

She added: “I’m sure if you talked to other ER doctors, they might have sent home people who might’ve had it. … I’m getting texts from people who have flu-like illness, fever, who are tested negative for flu. And they’re like, ‘Oh, I’m going to get tested now,’ and then they’re like, ‘It’s all a lie, there are no tests.’”

With no solid numbers, state and local officials have offered wildly varying guesses of the level of infection. On Thursday, the director of Ohio’s Department of Health, Amy Acton, said as many as 100,000 people in the state could have the coronavirus. The next day, she acknowledged that she was “guesstimating.”

Trevor Bedford, a computational biologist at the Fred Hutchinson Cancer Research Center who has been analyzing the outbreak in Seattle, said this was “certainly a strong overestimate.” An authoritative count maintained by Johns Hopkins University puts the U.S. total of cases at 2,952 and the world’s at over 156,000, as of the morning of March 15.

Will America’s New Testing Plan Work?

President Donald Trump declared a national emergency on Friday and promised, as he has before, that tests would be available to anyone who needed them. At a press conference that day, Trump announced partnerships with major national health care providers even as regulators gave emergency approval for use in the United States to new tests designed by Swiss health giant Roche.

It is not too late for large-scale testing in the United States to make a significant difference, said Vanderbilt’s Schaffner and Eric Feigl-Ding, a researcher at Harvard who is also a senior fellow at the Federation of American Scientists. “The U.S. doesn’t yet have a runaway epidemic like Wuhan or Italy,” Ding said. “Testing will be part of the containment that will flatten the curve,” the ongoing effort to slow the pace of infections so the health care system is not overwhelmed by a flood of patients needing intensive care.

Right now, additional testing will “clear the backlog,” confirming the illnesses of people who are already sick. But in the coming weeks, broader testing will help identify the “frontier” of the epidemic, the locations where new cases are breaking out, allowing epidemiologists to isolate the patients and trace contacts. “It’s like a battlefield,” Ding continued, “we need to get to the front lines. We can’t get there a week or two after the fact.”

Estimates range on how many tests the United States, with its population of 329 million, will ultimately need. Many put it at tens of millions in the coming months.

If the current approaches fail — and there are reports that key chemicals needed to run some of the tests are in short supply — American health care workers will be forced to treat everyone who has severe symptoms of the disease, a waste of resources since some will undoubtedly be suffering from other less serious respiratory illnesses and yet require the protective equipment and other precautions needed for COVID-19 patients.

Colin Furness, an infection control epidemiologist and professor at the University of Toronto, said deciding treatment without lab tests is “old school, but it works.” When China ran low on test kits, doctors started diagnosing COVID-19 based on people’s symptoms, Furness said.

“Whenever kits are short, there’s no question that’s what lies ahead,” Furness said.

“It’s a Failing”

While Trump said Friday in answer to a question from a reporter that “I take no responsibility” for the lack of tests, other officials have acknowledged flaws in the process. “It’s a failing,” Dr. Anthony Fauci, a member of the Trump administration’s COVID-19 task force, said on Thursday. “Let’s admit it.”

There seems little question that a critical misstep involved the CDC’s opting not to use the earlier test design approved by the WHO. On CNN Thursday night, Fauci was asked directly if that had been a mistake. He would not use the word but conceded that, looking back, it could well be seen that way. He offered little explanation for why the U.S. seemed so out of position on the question of widespread testing other than to admit the truth of it.

“The system is not really geared to what we need right now,” he said.

It will be months if not years before the U.S. failure to field tests in the crucial weeks in January and February of 2020 will be fully understood.

Jeremy Konyndyk said he saw a devastating lack of urgency in the White House’s approach to the pandemic. Konyndyk, who led the government’s response to international disasters as director of the Office of U.S. Foreign Disaster Assistance, said the government should have moved swiftly in the early weeks of 2020 when the virus overwhelmed the health care system in Wuhan with an avalanche of untreatable pneumonia cases, much like Korean officials did.

“We know that it was floating around in China undetected for some time before we realized they had it,” he said, “so we have to realize it’s a vulnerability here.”

Instead, he said, the CDC tried to create a more complicated test than the WHO’s that could tell the difference among coronaviruses. “It’s a neat idea if it works, but it smacks of letting the perfect be the enemy of the good,” said Konyndyk, now a senior policy fellow at the Center for Global Development, and a sharp critic of the government’s decision making regarding the virus.

“But that’s CDC’s normal standard operating procedure,” he said. “My impression is that it was less a conscious decision that, ‘We don’t like the WHO test and we don’t want to do it,’ and more just, ‘We’re going to do our own test because that’s how we do it.’

“I don’t think they saw it as urgent. And this, too, is inexplicable to me. We kept hearing from the administration that it was a low risk to the U.S., and I think they sincerely believed that. And it was low risk in the sense that if you see a forest fire sweeping towards you, burning up every town in its wake, but it’s three towns away, then they’re right, at this moment you’re not at risk of being burned alive.

“But that doesn’t mean you’re at low risk. It’s insane to me that they weren’t thinking of it that way. They were thinking that somehow between those three towns away — and us — there was some sort of fire break that would magically prevent us from being burned alive.”

Agnel Philip, Joshua Kaplan, Joseph Sexton, Nina Martin, Lexi Churchill and Beena Raghavendran contributed reporting.