The Bluetooth SIG is working on allowing wearable devices to be pinged in Exposure Notification Systems for the novel coronavirus, calling a smartphone-only approach to infection tracing "not a practical approach" for everyone. It will be a long time, though, before wearables become a viable detection vector.
The interest group points out that children or the elderly who don't tote a bulky slab in their pockets at school (if their school is open for in-person learning) or at care facilities.
Much like the ENS that Apple and Google are jointly maintaining, Bluetooth-enabled wearable devices like a wristband would log down pings with other devices throughout the day with anonymous ID keys. The log would be loaded back to the smartphone of a parent or guardian. If a person who is participating in the ENS reports a COVID-19 diagnosis, their log would be uploaded to a server and the primary device would check against it for any matching ID keys.
More than 130 SIG members are now participating in a working group for the spec extension. However, it'll take a few months before even a draft specification goes out.
Moreover, ENS operators would need to adopt a final version of that Bluetooth spec extension into their existing framework. And then there are the questions of where the bracelets come from and, in a related aspect, how much buy-in the community needs to give to make this branch-off tracing effort effective and worthwhile.
Still, ENSs are no replacement for the more complex process of contact tracing and widely-available, regular testing.