Health departments around the world are struggling to test for coronavirus and notify people who might have been exposed to the disease.Credit: Jeff Pachoud/AFP via Getty

“I’ve been in the ICU fighting … wait for it … Coronavirus!” tweeted a 38-year-old geneticist on Sunday. Clement Chow, from the University of Utah in Salt Lake City, was in a hospital intensive care unit (ICU) in Utah. Pretty soon, two dozen geneticists who had attended a meeting with him nine days earlier saw the tweet. Many were worried for Chow, and also upset that this was the first they had heard about it.

One member of the group saw the tweet just after having dinner with her 88-year-old mother, who has asthma, and her 84-year-old father-in-law, who has diabetes and a heart condition. She feared she could be infected, and might have transferred the virus to her family. COVID-19, the disease caused by the new coronavirus, is particularly dangerous for elderly people and those with certain medical conditions. Concerned about causing panic, she requested that her name not be used in this story.

Over the next 12 hours, the worried researcher and about two dozen others from 16 states scrambled to work out who they had spent time with since returning home from the meeting. They were upset that four days had passed between when their colleague was hospitalized with symptoms of COVID-19 and when they found out, through Twitter, that he had the disease. Another 24 hours would pass before an email from Utah’s public-health departments made it their way. Every passing minute, the virus has a chance to move to someone else.

“In the middle of a known pandemic, how is this not moving faster?” asks David Pollock, an evolutionary genomicist at the University of Colorado School of Medicine in Aurora who attended the meeting.

Dismal comparison

Across the United States, overwhelmed health departments are failing to diagnose people with COVID-19 and do the detective work usually used to contain outbreaks of contagious disease. This involves rapidly identifying the people with whom infected individuals have been in contact, requesting that close contacts quarantine themselves in their homes for two weeks, and testing them as soon as they have symptoms. The World Health Organization (WHO) considers these containment measures crucial because they reveal chains of transmission, and close them down before people have time to spread infections.

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Analyses of successful coronavirus responses in China, Singapore, Hong Kong and South Korea suggest that these regions curbed their outbreaks largely because of rapid testing, contact tracing and quarantine. One analysis found that of all the measures China put into place — including travel bans, school closures and lockdowns — early case detection and isolation packed the biggest punch. Without this measure, the study suggests, five times as many people would have been infected in the country by the end of February.

But US health officials seem to be deprioritizing this targeted approach in favour of social-distancing measures, as is the United Kingdom. Such behaviour is a matter of concern for the WHO, which recommends both strategies. “We have not seen an urgent enough escalation in testing, isolation and contact tracing, which is the backbone of the response,” said director-general Tedros Adhanom Ghebreyesus at a press briefing on 16 March. “We cannot stop this pandemic if we don’t know who is infected,” he said. “You cannot fight a fire blindfolded.”

Despite the relative wealth, laboratory capacity and education levels of the workforce in the United States, testing is alarmingly infrequent, and many health departments lack the staff required to identify and monitor dozens of close contacts for each confirmed case. But rather than blame testing labs and local health departments, some researchers have turned their ire on an absence of leadership needed to prioritize these measures and scal them up quickly.

“The fact that we learned about this from a Tweet points to a failure of our department of health,” says Nels Elde, an evolutionary geneticist at the University of Utah in Salt Lake City, who had shared a dinner plate with his hospitalized colleague before he was diagnosed. “But maybe we can come together with grass-root responses,” he says.

Varying policies

Policy on investigating contacts and quarantining them varies from city to city in the United States. In Denver, Colorado, where there were 49 confirmed cases as of 19 March, health officials reach out to people who might have been exposed only if they are elderly or have health conditions; they recommend that these people stay at home if they can. Health departments in at least two counties in California — Sacramento County (45 confirmed cases) and Placer Country (9 confirmed cases) — have decided not to quarantine contacts who show no symptoms, despite a growing body of evidence that asymptomatic carriers may transmit the coronavirus. And in Seattle, Washington (693 confirmed cases in the county), the health department is no longer routinely investigating contacts, because cases are proliferating rapidly and contact tracing is labour-intensive.

Many US cities have policies to trace contacts and ask them to quarantine themselves, but exposed individuals report hearing a confusing variety of instructions. Some have been told to stay at home for two weeks, or until they receive a negative test result. Others have been asked to avoid people who are most vulnerable to the disease, or to keep their distance from others. And many contacts have been alerted to their exposure several days later than they might have been, had these investigations been a priority. By comparison, in Singapore, medical teams have been told that after a person tests positive, they have two hours to work out and report who that individual might have infected.

A medical technologist tests specimens for coronavirus at Massachusetts General Hospital in Boston.Credit: Jessica Rinaldi/The Boston Globe via Getty

Once a population is saturated with coronavirus, it might no longer make sense to identify contacts, says Jonathan Eisen, a microbiologist at the University of California, Davis, but he doesn’t believe that the United States has reached that point yet. One modelling study estimates that there had been as many as 53,000 cases of COVID-19 in the United States by 14 March, more than the number of cases officially confirmed so far. But even if the estimate is correct , testing people and tracking their close contacts to the greatest extent possible, prevents a significant number of people from spreading the disease further, says WHO spokesperson Margaret Ann Harris. “China had shown that even with greater numbers, this is doable,” she says.

Eisen became upset on 9 March, when Sacramento announced that it would be winding down contact tracing. A few days later, the head of the county’s health-services department, Peter Beilenson, explained in a local paper, The Sacramento Bee: “We kind of lost the window of opportunity when you want to get a lot of people tested to do the contact tracing and the quarantining.”

Eisen disagrees, and says that another advantage of widespread testing and contact tracing is that it shows researchers how the outbreak is spreading. For example, studies suggest that the coronavirus survives on surfaces, in aerosolized droplets and in faeces. But he says we can’t truly understand how often it spreads through these vehicles without good contact tracing.

Testing shortfall

One root of the problem is a lack of rapid diagnostic testing, and a shortage of people required to investigate confirmed cases. Ranu Dhillon, an epidemic-response specialist and physician at Harvard Medical School, who is based in the San Francisco Bay Area in California, says test results are taking up to three days to come through — longer than they did in 2015 in West Africa during the Ebola outbreak, even though the basic methods are the same.

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For several years, Dhillon has published papers about the need for fast testing during epidemics. (The most recent one, he says, describes a situation like the present, but was rejected by journals for being “too alarmist”.) Now, Dhillon is waiting for his own test. This weekend, he asked for one because he had mild, influenza-like symptoms and wanted to be sure he wouldn’t infect his patients. But he was told that testing sites were closed on Sundays. “When I was in Guinea with Ebola, the response ran 24/7,” he says. “There were no weekends, because epidemics grow and transmit on mathematics, not on our schedules.”

Dhillon says that teams involved in testing and contact tracing in Guinea rapidly scaled up recruitment so they could work around the clock. That should be possible in the United States. Molecular biologists and other researchers have offered to join the response. Arthur Reingold, an epidemiologist at the University of California, Berkeley, says that about 60 graduate students in the school of public health there have volunteered to help local health departments. But he says some are waiting for permission from the federal granting agencies that pay them. Reingold adds that there are other obstacles, too. “It takes substantial resources to quarantine or isolate people,” he says.

But if the US forgoes contact tracing — or does it very poorly — in favour of aggressive social-distancing measures alone, the country risks the outbreak worsening, and lockdown measures such as school and business closures dragging on for longer than they would otherwise. And that, says Dhillon, will seriously damage people’s livelihoods and the economy.

Meanwhile, the geneticists who learned of their exposure through Twitter are taking their own temperatures. Another attendee of the recent meeting, a population geneticist in Oregon, tweeted: “we are all now self-quarantined. a few are showing symptoms.”