In the U.S., which now has more confirmed COVID-19 cases than any other country in the world, around 150,000 people are being tested for the virus each day. But that’s a fraction of the number of tests needed to be able to quickly contain any resurgence of the virus while we let people return to work and day-to-day life. By some estimates, we need to be doing 20 million to 30 million tests a day to get there. Even the more conservative estimates say we need to do at least half a million per day.

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Anyone with symptoms should be tested, along with anyone with likely exposure—such as healthcare workers or grocery store workers—and the contacts of anyone who tests positive, whether or not they have symptoms. Ideally, those contacts should be tested multiple times over the course of the incubation period if they don’t want to be quarantined. A sample of the general population should also be tested at random, since COVID-19 is often asymptomatic. “You want to identify enough of the people who are infected quickly enough so that they don’t spread the infection much further, and you can keep the disease at bay,” says Ashish Jha, the director of the Harvard Global Health Institute, which has estimated that the U.S. should run 500,000 to 700,000 tests a day by mid-May. “If we opened up our economy tomorrow and went back to work as though life was the same as in the pre-COVID-19 era, what would happen is infected people would start infecting uninfected people,” says Jha. “We know that the average infected person infects three. And those three would become 9, and 27, and 81, and 243. You get exponential growth. You would see within six weeks, eight weeks, a massive spike in cases and you’d have to shut down again. That’s just basic biology, basic math.” In the U.S., testing has been a problem from the beginning. As the coronavirus started to spread, botched test kits and shortages meant that American patients with obvious symptoms weren’t getting tested, let alone anyone else. As many as half of those infected with coronavirus may have no symptoms at all, meaning that they’ve been spreading the virus to others without knowing it. “The problem with the first round was that we were not prepared,” says James Zehnder, a professor of pathology and medicine at the Stanford University Medical Center. “We had no test to test people to see if they were infected. And there was a big delay in rolling that out, which allowed this infection to become a huge problem. Now, we’re playing catchup.” Other countries have tested at far higher rates, including South Korea, which quickly ramped up tests in the same week that its first cases were confirmed—and which has had far fewer deaths because it was able to identify people who were sick and isolate them so that they didn’t infect others. Without good testing, the U.S. ended up with stay-at-home orders: If you don’t know who’s infected, you have to assume that everyone is. Even now, as tests become more available, states can’t easily access the supplies that they need. In Maryland, after struggling to find test kits, the governor ended up buying half a million from South Korea. Other states have shortages of the swabs needed for testing. “I say to policy people, you realize we’ve shut our entire economy down because we don’t have enough swabs—how is this not just a travesty?” Jha says. “Millions of Americans are losing jobs. We’re losing hundreds of billions of dollars a day of economic activity because some states can’t find swabs? States are trying. They’re calling up everybody they can find who will be willing to sell them a swab, but this is no strategy for dealing with a pandemic.”

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The federal government should be leading the effort, he says, and coordinating an effort for manufacturers to rapidly ramp up production of swabs, along with other supplies that have experienced shortages, like the medium used to preserve samples in vials. “We don’t want the regular normal market to work itself out because it will literally take years,” he says. “What we want is rapid production. So a federal approach here would be really helpful.” Right now, each link in the supply chain is blaming another link for the lack of supply. Having a central authority coordinate the goals and output—like the War Production Board created for rapid production during World War II—could overcome those supply chain failures. Lab capacity will also need to increase. Some companies, like the health technology startup Color, are launching new labs that use automation to scale up the number of tests that can be completed each day. Tests should also go to the right places first. “It’s very important that nursing homes, homeless shelters, jails, prisons have access to testing,” says Josh Sharfstein, vice dean for public health practice and community engagement at the Johns Hopkins Bloomberg School of Public Health. “Our usual medical system doesn’t really respond to those settings that well. So there needs to be a concerted effort to make sure that testing is available where it’s most needed.” Estimates vary about the number of tests that are necessary. The Nobel Prize-winning economist Paul Romer has calculated that there should be 20 million to 25 million tests per day. A road map to pandemic resilience released by Harvard’s Safra Center for Ethics suggests that we need 5 million tests a day by early June to begin reopening society, ramping up to as many as 20 million a day by late July to fully reopen. The plan explains in detail what would need to happen over the next few months. As more and more people are tested, thousands of newly hired of “contact tracers” would find everyone who’s been in contact with an infected person so they can also be tested; everyone who’s infected would shelter at home and would be given support so they have food and other supplies and don’t lose their jobs. By May, as testing ramps up to 2 million tests a day, 40% to 55% of people could return to work; as cases decline by July, more people could return to work and some restrictions could be lifted on social distancing. By the end of July, as testing covered around 80% of the workforce, more people could return to work and the collective “stay at home” orders could lift. By August, with universal testing available, schools could reopen. The whole plan would cost between $50 billion to $300 billion over two years. Right now, the collective quarantine is costing $100 to $350 billion every month. The Safra plan might be the ideal scenario to save lives. But it would also be incredibly hard to increase testing that dramatically. Americans are also unlikely to be that patient—some states are already reopening now. Jha says that he agrees that tens of millions of tests a day would be good, but also calculated what he says is a bare minimum that could work. The larger number “is completely unrealistic in the short run, given that we’re doing 150,000 tests a day and we have not been able to make that number move in three weeks,” he says. “Even while we’re shut down, we can’t figure out how to increase our testing.” Jha and other researchers looked at the number of new cases that they expect will happen in May, and calculated that half a million tests a day would be sufficient. “If you wake up one morning and you have a fever and you have a sore throat, you should be able to pick up the phone, call somebody, and go get tested that morning,” he says. “And if you’re positive, you get a phone call from a public health worker who does contact tracing and identifies everybody you’ve hung out with in the past five days. And then they call all those people and get all of those people tested. And that’s how you can pick up a bunch of asymptomatic carriers . . . it’s public health 101. If you go through this strategy, you have a pretty good shot of getting most people who are infected on any given day.”

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Another type of test that looks for antibodies in the blood that suggest that someone had the virus could also be helpful. Right now, the quality of those tests is variable, and someone could easily get a false positive and think that they might be immune. It also isn’t clear yet how immunity works with the illness; in Korea, some patients who had seemed to recover have now tested positive again. But antibody tests can help researchers better understand the virus. The main test used now looks for viral RNA to see if someone is currently infected. It uses a method called polymerase chain reaction (or PCR) that’s about 20 years old; it’s not something that could be scaled up to 20 million tests a day. “We need new technologies,” Jha says. “There are all sorts of cool new technologies that companies are starting to get into and trying. I think what the federal government should be doing is putting a bunch of resources into play and giving out awards and prizes for companies that can do massive breakthroughs, really kind of priming the market to incentivize a lot quicker development of technology. I do think big technological breakthroughs are coming. I want to speed it up.” For now, he says, we can scale up the tests that exist and hire at least 100,000 people to handle contact tracing, perhaps with some support from apps that also try to trace the spread of the virus. “The bad news is that we have 22 million people who’ve lost their jobs in the last month,” Jha says. “But it does open up a pool of people who would love to go back to work, be hired to do this. They can get trained. And it would give those people jobs. It would help us bring this disease under control and it would be pennies on the dollar compared to the hundreds of billions of dollars that we’re putting into the stimulus to try to help people through this difficult time. We could actually invest it in building a little public health workforce.” If the federal government doesn’t lead the overall effort to scale up testing, contact tracing, and support those who have to be isolated, states will be forced to do it themselves. Right now, widespread testing is happening only in a handful of areas, including the small town of Bolinas, California, which is testing every citizen, and in Utah and Iowa, which are actively trying to scale up testing of as many people as possible. California is also beginning to scale up its own tests statewide. “What I suspect will happen is some states will figure it out and make great progress and open up their economies and keep them open, and other states are going to struggle and really have a hard time,” Jha says. “And I think that’s really unfortunate, because obviously this would be much better if we could all do this together.”