Outside Harrods department store, London, on April 16. | Chris J Ratcliffe/Getty Images
Despite warning of “unintended consequences,” the UK is forging ahead with its new app.
The United Kingdom’s digital contact tracing app is almost here, and even the organization behind it admits it’s still a work in progress that has the potential for “unintended consequences.” It also may be a troubling preview of how digital contact tracing during the coronavirus pandemic will play out in the United States as a disparate network of statewide contact tracing programs is starting to roll out.
In order for a contact tracing app to actually work, it has to have widespread adoption. So if an app doesn’t have the confidence of its intended users — due to privacy concerns, functionality issues, or even because of questions over its legality — people won’t use it. On the other hand, an app that preserves privacy too well won’t give public health authorities enough information about the virus’s spread for a proper response. The UK joins the US, France, Germany, Singapore, and many other countries in trying to strike the difficult balance between making an app that’s both usable and useful.
Trials of the UK’s National Health Service (NHS) app have begun on the Isle of Wight, an island off the southern coast of England with a population of about 140,000 (who seem to have mixed feelings about being the UK’s contact tracing guinea pigs). Government workers were given access to the app on Tuesday, with the rest of the island’s population being able to use it on Thursday. The results of the pilot program will determine if and when the app is rolled out across the country.
The app has been somewhat controversial due to the NHS’s decision not to use the Apple-Google exposure notification tool, which is set to be released in mid-May. Like many others, both the NHS contact tracing app and the Apple-Google tool rely on exchanging Bluetooth signals with nearby phones. But while the Apple-Google tool heavily restricts the amount of data exchanged, the NHS wanted more information and control than Apple-Google would allow, forcing it to go it alone.
“An app that provides fantastic provable privacy but doesn’t help stop the spread of the disease isn’t a useful tool,” Ian Levy, technical director of the UK’s National Cyber Security Centre, which helped develop the app, said in a blog post.
Primarily, the NHS wanted a centralized system, where the Bluetooth keys of both infected people and those they came in contact with are stored in a database kept by the NHS. The Apple-Google tool is decentralized, so only an infected person’s anonymized Bluetooth keys are uploaded to a server. Data about any matches with devices that came in proximity to the infected person stay on those devices’ phones without getting uploaded to a central server.
This is more private, but it also means public health authorities get very little data. Some, like the NHS, say they need more data to study how the virus spreads, but some of this data, like postal code information, could be used to identify specific users, causing privacy concerns. Furthermore, the NHS hasn’t ruled out adding more identifying information to the app in the future, such as collecting location data.
The NHS doesn’t have the best reputation when it comes to keeping patient data secure and private, making it harder for citizens to trust that it will be able to protect the data it gets from the app. Matthew Gould, who heads up the NHSX, the NHS’s tech and data arm, recently admitted that he was unable to give Parliament “a definitive list of exactly who would have access to the data,” which isn’t exactly reassuring.
There are other issues with the NHS app beyond privacy concerns. Without the Apple-Google tool, Apple devices won’t be able to exchange keys if the app isn’t open, which could drain a device’s battery life. The Australian government encountered this problem with the recent release of its own centralized tracing app. The NHS app is also much likelier to generate false positives, as users can self-report symptoms, triggering warnings to their contacts even without confirmation that someone has the coronavirus.
The UK is not the only country that thinks the Apple-Google tool has a little too much privacy while offering health authorities too little control. France similarly decided that a centralized system is more important than the technological advantages of the Apple-Google tool (the French app is set to begin testing next week). But other European countries, including Germany, Italy, and Switzerland, are backing the decentralized approach, though it’s not yet known if any of them are using the Apple-Google tool.
In the US, no individual states nor the federal government have yet committed to using the Apple-Google tool. Some states, such as Utah and North Dakota, are already using their own digital tracing systems and seeing limited success, given the North Dakota app’s reported 3 percent adoption rate. Several others, including Colorado and Louisiana, told Recode they have no plans to use the tool in any apps they develop.
What remains to be seen — and what many experts have expressed significant doubts about — is if any of these digital contact tracing apps, centralized or not, will be widely used upon their release. Singapore’s experience, where only a fifth of the population downloaded its TraceTogether app, doesn’t bode well. One commonly cited report suggests a minimum adoption rate of 60 percent of the population for a contact tracing app to be effective.
When participation is voluntary and opt-in, the onus is on health authorities to make their apps as palatable as possible to the general public. For many, that will include those apps giving minimal data about their contacts and health status. A centralized database doesn’t do that, and that might be one obstacle too many for this NHS app to do what the agency hopes.
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