Within weeks of Covid-19 shutting down the world in 2020, teams at archrivals Apple and Google partnered on a rare joint project. They developed a way to log people’s proximity using Bluetooth chips in iPhones and Android phones, enabling the creation of apps that let someone who tested positive for the virus to anonymously notify fellow users whom they’d been near in the preceding few days. Those alerted to the exposure could then isolate, test, and quarantine, hopefully slowing the spread of Covid.
Covid is still around, but the grand experiment in semi-automated contact tracing by smartphone is now nearing its end in the US, following similar shutdowns in many other countries as concerns about the virus have eased.
On May 11, the Biden administration will stop paying for the two cloud servers that underpin the US system and power exposure-tracking apps offered by individual states. States will now have to boot up their own servers, and in many cases redesign their apps, if they want to keep the alerts flowing. Though a few, including California, are considering the idea, it remains to be seen whether any will follow through. California’s Department of Public Health did not provide comment for this story by publication time.
Virginia, Massachusetts, and New Mexico confirmed last week that they will be bowing out. Wisconsin deactivated its app on April 3. “We were very clear up-front that it comes down when we no longer need it,” says Jeff Stover, chief of staff for the Virginia Department of Health, the first state agency in the US to launch exposure notifications. “Doing what we said we are going to do, it’s going to instill a little bit more public trust.”
Google and Apple, which said in a 2020 FAQ that they would disable the system regionally when “it is no longer needed,” so far aren’t pulling the plug on their end. Apple spokesperson Zaina Khachadourian and Google spokesperson Christa Muldoon say the companies plan to keep supporting state exposure-tracking apps that are updated to keep working after the federal shutdown.
At the height of the pandemic, millions of people in the US activated exposure notifications, as Apple and Google call them. The system arrived as a way to make loosening of strict lockdown measures safer, enabling people to be around one another without massively accelerating the spread of the coronavirus. Making Bluetooth signals the foundation of the system was inspired in part by US high schoolers’ prototype for automating contact tracing for Ebola in rural Africa.
Public health authorities insist that exposure notifications have been a success, preventing infections by prompting people to isolate or test, and demonstrating the potential for public health apps. Critics say too few Americans turned on exposure notifications to make them truly useful. Concerns about whether anonymity would be preserved deterred some people from switching alerts on, and states struggled with limited marketing budgets to fight back. Measures such as vaccinations, face masks, and rapid tests became bigger contributors to people feeling comfortable about leaving the home.