Contact tracing works best as part of what experts sometimes call the Swiss cheese model, which involves layering several strategies. One method may have holes, but many combined can form a solid block.
Do this right, and “you could almost stop a pandemic in its tracks,” says Rajeev Venkayya, who was part of the US team that helped design the George W. Bush administration’s plan to deal with future pandemics.
For covid, the appropriate layers would include comprehensive testing, effective contact tracing, and social distancing—but with few of those layers in place, the virus ran wild. And once the spread is rampant, contact tracing simply isn’t enough.
The promise ahead
Despite its shortcomings, digital contact tracing may still have a future. The arrival of multiple vaccines gives hope that case numbers will drop to manageable levels. At that point, Venkayya says, “having all the tools that we can at our disposal—including robust testing and tracing—will be really important. You are just trying to keep up and to limit the damage that’s being done.”
In the US, as the Biden administration gets up to speed, federal or national solutions (like pushing for nationwide use of contact tracing apps) may be part of the answer—along with monitoring tools like Bluetooth beacons, tracking bracelets, and QR codes that you scan to enter a cafe or workplace.
But the most important takeaways from our global experiment with exposure notifications may be less about the technology and more about how to implement it. The glitchy rollout has made it clear that introducing innovations—for this pandemic or the next—will require us to build trust, increase access and equity, and consider technology’s place in complex systems.
Progress, of course, is about looking ahead. But as contact tracing reminds us, it’s just as important to retrace our steps.