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The practice of contact tracing – or the identification, assessment and management of people who have been exposed to disease – is an essential tool in controlling epidemics by disrupting the chains of disease transmission. . And indeed, combined with lockdowns and prescriptions on masks, some countries have had great success using contact tracing to reduce outbreaks.
So why have attempts to institute it failed in so many other countries, especially the United States? And given that COVID is likely to be with us in one form or another for a while, are there ways to make contact tracing more effective here?
Sarit Markovich, clinical professor of strategy at the Kellogg School, says contact tracing is all about trust. This means that confidence will have to be the basis of any successful effort to move forward. This includes building confidence in technology, especially in terms of false positives, confidence that information will be kept private, and confidence that people will not suffer consequences for self-reporting.
Here, she offers her thoughts on where contact tracing can fail and how to do it better.
Consider your social makeup
Contact tracing requires individuals to share private information in the service of the public good. By considering how to solicit this information, it helps to understand the difference between centralized and decentralized societies, says Markovich.
How technology can help
Not all contact tracing technologies are created equal.
GPS, which was the first option at the start of the pandemic, works by pulling location data from phones. But it can’t pinpoint a specific location or explain the passage of time, two variables critical in determining exposure risk, Markovich says. Research shows that, on average, GPS accuracy is between seven and fifteen meters. It may be negligible in other contexts, but with contact tracing, inaccuracy can have a profound impact on people’s lives.
“With GPS, the standard error is very large,” says Markovich. “It doesn’t take space or time very well into account. So if you go to Sam’s Club and walk through the store [from an infected individual], you may receive a notification that you need to self-isolate, even if, in essence, you were not near the infected person. On the other hand, if someone sick walks in and out of an elevator just ahead of you, but presses the button which you then press, GPS technology won’t pick it up, ”which leads you to think that you are in the clear when you have actually been exposed.
There is also the issue of privacy: people may not want their communities or their employers to know where they are going at all times of the day.
Bluetooth technology works by allowing phones to exchange signals with other phones nearby. When phones scan each other, they exchange anonymous data, including ID codes, approximate distance and duration of contact. An app then issues “exposure notifications” to users who were nearby for at least 15 minutes.
This technology has one big advantage: it is more accurate (unless someone else is using your phone) and it protects privacy better because it tracks proximity to others rather than location.
But because both are opt-in services (users turn on their devices and accept notifications), phone-based contact tracers will only see a fraction of a user’s contacts.
Encouraging people to trust the technology and improving its accuracy will make them more likely to comply with quarantine requests. Because who wants to quarantine for two weeks when we suspect a false positive?
In countries with centralized governments, like China or Singapore, contact tracing is mandatory and compliance is universal. Governments track people’s movements through a national phone app or portable tokens, which people scan as they move from place to place. Non-compliance is heavily sanctioned. In general, these societies prioritize collective well-being over individual freedoms, such as privacy.
“If the government forces you to do it, you do it,” Markovich sums up. “And now, in a lot of these places, people are back to their desks and to their normal lives.”
But in democratic societies where government is decentralized, individual rights can be in tension with public health, Markovich says. Strategies that work in centralized societies are less likely to work in decentralized societies.
In Israel, for example, the government has made digital contact tracing mandatory and imposed heavy fines for non-compliance. Considering the size of the country’s population and relative homogeneity, it looked like national contact tracing would work roughly as it did in Singapore, Markovich says. But people objected to being followed. They turned off or left their phones at home, and the initiatives failed.
“In decentralized societies, people don’t fully trust the technology and don’t fully trust the authorities knowing where they are,” says Markovich. “They want privacy.”
Less technological approaches, where public health workers individually ask exposed people about their contacts, are unfortunately no longer promising.
In Israel, for example, a volunteer-run startup attempted to launch in-person contact tracing as an alternative to the government’s digital model. The initiative failed when it turned out that residents did not want to share personal information with strangers. That same skepticism exists in the United States, where 41% of people polled in a recent Pew poll said they would not speak to a public health official who contacted them by phone or text.
“The goal is to get people used to contact tracing in a context that is not scary and in a way where its effect on others is not negative but positive,” she says.
Keep it local
For now, Markovich believes that in decentralized societies, national contact tracing initiatives will not work. A better option: to leave the driving to governments and local organizations.
At this smaller scale, Markovich says contact tracing becomes easier to centralize. Initiatives can be strongly encouraged or even mandated, and application is also easier when linked to social pressures from local communities or demands from employers.
“Organizations and municipalities have an advantage because there is more trust involved,” says Markovich. “They can centralize it and mandate it, because if you want to be part of an organization – an employee of your company, for example – there are rules that you will have to follow.”
Over time, Markovich believes the number of organizations and communities mandating contact tracing will increase, especially as more local models – a church, factory, or town whose leaders have established trust – will begin to succeed.
Disclosure of rewards without punishing exposure
She also advises local communities and organizations to think carefully about how to encourage people to disclose their contacts. It is above all about minimizing the negative consequences for all parties: those who have tested positive and disclose their contacts, as well as the people they have exposed.
Here, technology has a powerful role to play. Markovich observes that in some communities, people with HIV are accused of spreading the virus. This practice of “COVID-shaming” could make them less likely to self-report their contacts.
“This is where the technology helps,” says Markovich. “You want to use technology rather than relying on people to tell you who they’ve been in contact with or that they’re sick. It is not about self-declaration. Technology tells you that.
But despite the benefits of technology that can automatically alert people to exposure (see sidebar), Markovich also notes that the human element shouldn’t be ignored. Follow-up calls from trained professionals will allow people to ask questions about next steps, voice concerns, and learn to self-isolate, if necessary.
“The human part is important,” says Markovich. “The technology is great in terms of detection speed, but human contact creates trust. “
And regardless of the technology used, if people are to be quarantined because they have been exposed to COVID, employers should assure their employees that they will be compensated for the time they self-isolate. Markovich cites incidents in which employees who were exposed to the virus went to work because they did not have paid sick leave or feared losing their jobs. Since some areas are at higher risk of infection, such as grocery stores, the government should share these costs with organizations.
“We need incentives to encourage people to speak the truth and to feel comfortable staying at home,” Markovich said. “If you know that you are going to be compensated even though you are at home, then you will certainly feel more comfortable coming forward and isolating yourself. “