By John Gruber
Double the brightness of your MacBook Pro and Pro Display XDR. Try Vivid for free!
Fewer than half of U.S. states offer Android and iOS tools for the “exposure notification” system the two companies announced last April, which estimate other people’s proximity via anonymous Bluetooth beacons sent from phones with the same software.
Most people in participating states have yet to activate these apps. Those who do opt in and then test positive for the coronavirus that causes COVID-19 must opt in again by entering a doctor-provided verification code into their apps.
That second voluntary step generates anonymous warnings to other app users who got close enough to the positive user for long enough — again, as approximated from Bluetooth signals, not pinned down via GPS — to risk infection and to need a COVID-19 test.
So if your copy of one of these apps has remained silent, you’re not alone.
“Nobody in my circle has gotten the phone alert,” said Jeffrey Kahn, director of the Johns Hopkins Berman Institute of Bioethics in Baltimore and editor of a 2020 book on the ethics of digital contact tracing.
I’ve been curious about this for a while, so I asked on Twitter whether any of my followers had gotten notifications through this system. A few have! But I think the whole idea is fundamentally flawed. Even putting aside the fact that fewer than half of U.S. states offer the apps — a big issue to put aside — the only people who are using them are people who are conscientious about COVID exposure in the first place.
New Jersey has a population of about 9 million people. As of today, there have been about 800,000 cumulative reported cases of COVID-19 in the state. 600,000 users have used their app since it was launched. Via information displayed in the app itself, the total number of users who’ve uploaded their randomized/anonymized IDs after testing positive? 1,046. The total number of users who’ve been sent an exposure alert notification? 1,894. (My home state of Pennsylvania uses the same “COVID Alert” base app as New Jersey, but doesn’t seem to publish any numbers regarding usage.)
The whole endeavor seems pointless, looking at these numbers. If anything, it might be giving the users of these apps a false sense of security. If you use one of these apps and are exposed to someone who later tests positive, the odds that that person both uses the app and will report their positive test result seem not just low but downright infinitesimal.