5 thoughts on “Details on Apple-Google Digital Contact Tracing System using Bluetooth technology”

1. The basic idea is that as jurisdictions flatten the curve of infection and begin to consider re-opening parts of society, they need to implement a comprehensive “test and trace” scheme. You want to test people widely and thoroughly for the disease, as this article by Umair Irfan from Monday explains. And then, as you discover new cases, you want to see who those people may have come in contact with during the time that they were infectious.

   Historically, this has been a manual process. Since the COVID-19 outbreak began, some countries have turned to technological means in an effort to enable public health authorities to find more people who may have been exposed and do so more efficiently. So far, it’s not clear that tech-enabled contact tracing has been all that effective. The system relies on voluntary participation, which has generally been weak. And the Bluetooth technology on which the system depends carries with it a high potential for false positives: it’s just not powerful enough to distinguish between cases where people were in very close proximity from ones in which they were 15 or more feet away.
   The biggest concern most people have expressed about the collaboration is that it will lead to damaging privacy violations. Democratic senators have led the charge here, sending an open letter to the companies expressing their fears. I’m less worried. For one thing, Apple and Google’s system is cleverly designed to maximize individual privacy; it avoids capturing location data and instead records only the proximity of your smartphone to someone else’s. And for another, I value my own privacy less during a public health emergency. I trust Apple and Google to prevent my personal health information from being identified as mine and shared with others, but given the design of the system, I fail to see how a breach would be catastrophic even if it did somehow materialize.

   The second set of concerns has to do with how the system will work in practice. Apple and Google answered a lot of questions about that subject today; here are what I took to be the most consequential.

   First, the companies said that by phase two of their effort, when contact tracing is enabled at the level of the operating system, they will notify people who have opted in to their potential exposure to COVID-19 even if they have not downloaded the relevant app from their public health authority. My understanding is that the operating system itself will alert people that they may have been exposed and direct them to download the relevant public health app. This is significant because it can be hard to get people to install software; Singapore saw only 12 percent adoption of its national contact-tracing app. Putting notifications at the system level represents a major step forward for this effort, even if still requires people to opt in.

   Second, Google said it would distribute the operating system update through Google Play services, a part of Android controlled by the company that allows it to reach the majority of active devices. (Google says it will be available to everyone running Android 6.0, also known as Marshmallow, and higher on devices that have the Google Play store.) This is highly preferable than relying on carriers, which have historically been slow to distribute updates. It remains to be seen exactly which devices will be eligible for the update, on Android as well as on iOS. But it seems likely that the companies will be able to reach most active devices in the world — a significant feat. (Related: someone asked the companies what percentage of the population we need to use the system to get it to work. No one knows.)

   Third, the companies said they would prevent abuse of the system by routing alerts through public health agencies. (They are also helping those agencies, such as Britain’s National Health Service, build apps to do just that.) While the details are still being worked out, and may vary from agency to agency, Apple and Google said they recognized the importance of not allowing people to trigger alerts based on unverified claims of a COVID-19 infection. Instead, they said, people who are diagnosed will be given a one-time code by the public health agency, which the newly diagnosed will have to enter to trigger the alert.

   Fourth, the companies promised to use the system only for contact tracing, and to dismantle the network when it becomes appropriate. Some readers have asked me whether the system might be put to other uses, such as targeted advertising, or whether non-governmental organizations might be given access to it. Today Apple and Google explicitly said no.

   Fifth, I’ve heard conflicting claims about the ability of Bluetooth-based tracking to measure distances. Last week I told you that Bluetooth could not distinguish between phones that were within six feet of one another, in contradiction of advice from public health agencies, and those that might be 20 or even 30 feet away. One reader pointed me to a part of the Bluetooth standard known as received signal strength indication, or RSSI, that is meant to offer fine-grained location detail.

   So, to wrap up: do we feel more or less optimistic today about tech-enabled contact tracing than we did before?

   I still think that digital contact tracing is unlikely to be one of the two or three most important aspects of a country’s coronavirus response plan. Experts have told me that social distancing, wide-scale testing, and isolating sick individuals are significantly more important. And when it comes to contact tracing, we know that human beings often do a better job than smartphones — and some have argued that we need to hire hundreds of thousands of them to do the job.

   At the same time, it’s possible to see how digital contact tracing could at least complement other, related efforts, including manual contact tracing. Compared to what, say Hong Kong is doing to test and trace, distributing digital tracking bracelets to everyone getting off the plane at the airport, what Apple and Google have proposed can only be described as a half measure. But in the United States at least, it may be the case that a series of half measures are all we will have to rely on.

   https://www.theverge.com/interface/2020/4/14/21219289/apple-google-contact-tracing-app-android-ios-pros-cons-quarantine-testing

2. Normally I do not read articles on tech blogs, but this write-up of the Apple-Google contract tracing system was an exception! Your writing style is amazing. Thanks, for a comprehensive and very well documented article.

3. Great article on Apple-Google contact tracing system. It’s unusual to see cooperation between these tech giants.

   Each public health authority in each country or region must first agree to adopt Apple and Google’s Exposure Notification API. Next, the health authority must create an iOS and Android app for their region dedicated to supporting Exposure Notifications.

   In the United States, rather than creating a single contact tracing app, the decision to support Exposure Notifications is made by each state’s public health authority. Alabama, South Carolina, and North Dakota are among the first U.S. states to express interest in Apple and Google’s Exposure Notifications API for assisting COVID-19 contact tracing.

   https://9to5mac.com/2020/11/30/covid-19-exposure-notification-api-states/

   Support for Washington, Minnesota, Maryland, Washington D.C., Connecticut, and California was added for iPhone and Android on November 30, 2020.

   Which U.S. states are using Apple’s Exposure Notification API?
   States Status
   Alabama Available (Apple/Google)
   Alaska Not Available
   Arizona Available (Apple/Google)
   Arkansas Not Available
   California Pilot Rollout (Apple/Google)
   Colorado Available (Apple/Google)
   Connecticut Available (Apple/Google)
   Delaware Available (Apple/Google)
   Florida Not Available
   Georgia Not Available
   Hawaii Not Available
   Idaho Not Available
   Illinois Not Available
   Indiana Not Available
   Iowa Not Available
   Kansas Not Available
   Kentucky Not Available
   Louisiana Not Available
   Maine Not Available
   Maryland Available (Apple/Google)
   Massachusetts Not Available
   Michigan Available (Apple/Google)
   Minnesota Available (Apple/Google)
   Mississippi Not Available
   Missouri Not Available
   Montana Not Available
   Nebraska Not Available
   Nevada Available (Apple/Google)
   New Hampshire Not Available
   New Jersey Available (Apple/Google)
   New Mexico Not Available
   New York Available (Apple/Google)
   North Carolina Available (Apple/Google)
   North Dakota Available (Apple/Google)
   Ohio Not Available
   Oklahoma Not Available
   Oregon EN Express app in development
   Pennsylvania Available (Apple/Google)
   Rhode Island Not Available
   South Carolina Will Participate
   South Dakota Not Available
   Tennessee Not Available
   Texas Not Available
   Utah Not Available
   Vermont Not Available
   Virginia Available (Apple/Google)
   Washington Available (Apple/Google)
   West Virginia Not Available
   Wisconsin Not Available
   Wyoming Available (Apple/Google)
   District of Columbia Available (Apple/Google)

   *Some states and territories may not opt-in to supporting a contact tracing app that uses Apple and Google’s exposure notification API.

   Best wishes and good health to everyone!

4. This kind of collaborative work by Google and Apple pleases me very much. Thanks for the update.

5. Awesome content, I love it. What’s the result of the Apple-Google contract tracing partnership?

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