The rise of the Delta variant is sparking all sorts of memories—the anxiety amid the first Covid wave in spring of 2020, the crushing winter surge, the unceasing debate about “nonpharmaceutical interventions” such as masking and distancing, the concerns about kids and schools. But it hasn’t seemed to bring back discussions of contact tracing, one of the first best hopes for containing the pandemic in its earliest days.
Contact tracing has been declared dead many times before. Four and a half months after Covid-19 was first identified in the US, The New York Times said it was failing in many states. And indeed it was, if failing is equated to not stopping the pandemic. One year later, as the country confronts another deadly wave, it seems it’s disappeared from the equation almost entirely. Earlier this summer, a Covid-19 viewpoint in JAMA titled “Beyond Tomorrow” sketched out four possible outcomes for SARS-CoV-2—elimination, containment, cohabitation, and conflagration. It did not include any mention of contact tracing. Covid endgame articles in July and August in The Atlantic and STAT, from reporters who have led the way on coronavirus coverage, similarly said nothing about the role of contact tracing in bringing the pandemic to a close.
What media attention it has received of late has been grim: A recent Kaiser Health News story described contract workers and a public fatigued by the Delta surge. “Contact tracing seems to have fallen by the wayside,” it noted. The story documents fewer workers in states such as Arkansas and Texas to alert people that they’ve been exposed to the virus and advise them on isolation. And Texas’ new budget bans state funding for contact tracing altogether.
In June of this year, just before Delta became the dominant strain in the US and the pandemic looked to be easing up, a survey by the Johns Hopkins Center for Health Security and NPR found that many states were winding down their contact tracing efforts. But just as masking and social distancing are now making their comebacks, so too must contact tracing. Fighting the newest variant of the world’s newest virus will require the help of one of the oldest public health practices—one that’s credited with playing an important role in ending smallpox and SARS-1, and that has been routinely used over the years (along with vaccines and treatments) to contain tuberculosis, measles, Ebola, and various STDs. As the nation struggles to hold back yet another wave, contact tracing can not be allowed to fade away.
From the very early days of the pandemic, contact tracing has had a rough go of it. “It was started way too late,” says Emily Gurley, an epidemiologist with the Center of Global Health at Johns Hopkins, who created an online course to train contact tracers, with more than a million sign-ups so far around the world. State and local health officials began gearing up in the spring of 2020, but were hampered by the lack of easily available testing—symptomless subjects went unrecognized, and their contacts uninformed. Over time, government efforts to contact trace have waxed and waned, slacking off at surges when contact tracers were detailed to vaccination efforts, dropping during those welcome troughs in incidence.
The methods deployed for contact tracing in this pandemic—personal calls and impersonal apps—have been far from perfect, and concerns about privacy abound. As WIRED has reported, the use of apps for contact tracing has pretty much failed in the US. In the UK, people complain about a “pingdemic”—getting notifications from a widely used app that is so sensitive people in the next flat might get a message even though they’d never been in the same room with the infected person. In one week this summer, 690,000 people in England and Wales received isolation notices, according to The Washington Post, and businesses complained that so many workers were staying home they couldn’t stay open. The apps are, let’s say, a work in progress.
No public health measure is perfect, and a single one is never going to be able to handle the pandemic on its own. But layering them all—contact tracing included—is our best hope. From the beginning contact tracing was meant to limit spread but was never expected to stop it completely, says Gurley. SARS-CoV-2 spreads too efficiently and with too much of a lag time between infection and symptoms. Other nonpharmaceutical interventions have shown their limits as well—strict lockdowns have proven to be unpopular, masking and distancing work but are used inconsistently. Gurley and others see contact tracing as an adjunct, harder to do when the pandemic is surging as it is now, but still worthwhile as an added layer of protection. “The increasing case counts and infectivity make measures to stop transmission even more important,” she says.
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“There's always some benefit to doing contact tracing because the more people you reach, it's that many less people who might become cases,” says Marcus Plescia, the chief medical officer of the Association of State and Territorial Health Officials. “You may only be getting a percentage, but, with that percentage, you're making a difference.”
One reason for the relative silence about contact tracing at this stage is a lack of data on how it’s performed, the relative value of various approaches, and, perhaps most importantly, its cost effectiveness. The scientific literature is remarkably free of publications about contact tracing—overworked health planners have been busy trying to get programs up and running. “How effective and how important contact tracing has been in our efforts to control the pandemic is still to be determined,” says Plescia. He predicts that when researchers look back at this time, its benefits will be clear.
A recent “natural experiment” published in the Proceedings of the National Academy of Sciences shows a big payoff when done properly, at least in the United Kingdom. In early October 2020, the people running England’s national Test and Trace program noticed that reports about nearly 16,000 people had been left off an Excel spreadsheet that alerted tracers to search out those people’s contacts. An estimated 48,000 people were not told they’d been exposed to someone carrying the virus for five days or more.
Thiemo Fetzer of the University of Warwick and Thomas Graeber of the Harvard Business School used regression analysis and assumptions about the course of the pandemic to calculate what that delay meant. They concluded that in the six weeks following the glitch, contact tracing in the areas it was used reduced new infections by 63 percent and deaths by 66 percent. It must be said that those estimates were made using pre-Delta data, and are for England, which has a national test-and-trace system that’s widely used and pretty well accepted by the public; there’s no telling what the effectiveness might be in the US, with its current patchwork system of passive and active contact tracing programs that ramp up or slack off as political support waxes and wanes. But it’s clear the potential is enormous.
In the time of the super-transmissible, super-infectious Delta variant, contact tracing is even more essential. “Reaching cases and getting them to isolate is exponentially more effective [than it was with previous variants]” says Plescia. The CDC says the Delta variant is more than twice as contagious as its predecessors. “Every time you can get a case to understand the importance of isolating and not being in contact with others, that's a big leap in transmission that you're preventing.”
Tom Frieden, former CDC head and now chief of the non-profit health initiative Resolve to Save Lives, is also pushing for more and better contact tracing. “We have to think of contact tracing as a way of understanding more about the virus,” he says. “There’s a wealth of information that can be gotten from contact tracing.” Among other things, contact tracing initially allowed epidemiologists to recognize how fast the Delta variant was spreading.
A Resolve to Save Lives manifesto lists a slew of other advantages: It identifies hot spots; it can reduce transmission in schools and avoid school closings; it leads to an informed community. And, Frieden says, the information it provides could play an important role in ensuring that vaccines are targeting the most at-risk populations. That said, while the speed and infectiousness of Delta does make contact tracing more worthwhile, it also makes it more difficult, he notes.
This new phase of the pandemic, and the reality that it may be endemic, also means contact tracing has to evolve in order to meet the moment. Frieden would begin with rebranding. “We shouldn’t call it contact tracing,” he says. “It’s Covid support services. And we need to provide support to people who have the infection.” That’s something few programs do today—help people after they’ve been notified of an exposure. This could include providing housing for people who can’t isolate within their own homes and other comprehensive services so they can access care, afford to not work, and don’t have to leave home. To be effective in the long term, contact tracing needs to be coupled with assistance while isolating.
Fortunately, some improvement in contact tracing programs may now be possible. The American Rescue Act signed into law in March provides $47.8 billion to the Department of Health and Human Services for Covid-19 programs at the federal, state, and local level, specifically including testing and contact tracing. There’s $7.7 billion in the act for a public health workforce, and states don’t have to use all the money they’re getting in the first year—they can extend it out so they can train and hire people over several years. The Paycheck Protection Program and Health Care Enhancement Act includes $25 billion for Covid-19, with some of it going toward contact tracers.
With better funding and a professed government interest, contact tracing could finally have its day. “I hope it will,” says Frieden, “but it’s going to require building trust in the community, it’s going to require a culture of using data to improve performance, it’s going to require a kind of relaunch of contact tracing because the way it was done in the US was very ineffective. It’s not that it failed everywhere, it failed here.”
Going forward, it doesn’t have to.