COVID - 19 app

The government and NHS have released their new Covid-19 app. After their disastrous trial on the Isle of Wight, it can be assumed that things have been ironed out enough to roll out for general release. It works via Apple's/Googles Covid-19 API which allows phones to handshake each other over Bluetooth. This API is only provided to healthcare authorities so other app developers aren't able to exploit it to make other apps. It takes the much talked about de-centralised approach to contact tracing, meaning that in theory, the app developer/government wont know which users have been in contact. Countries trying to do the centralised approach have been struggling as Apple refused to let app developers meddle with the Bluetooth settings so have had to adopt this de-centralised approach. Below is the rough blueprint of the two systems.

And how Apple/Google's system works:

The NHS app works by creating a score from how close you are and long you are next to someone. A score above 900 will trigger an alert to your phone if that contact registers themselves as positive. 

One of the flaws of this app is that you have to voluntarily submit a positive test to the app. Obviously it should be your moral duty to do so, but some may not to do so and thus defeating the purpose of the app. Also despite over a million apps downloaded in England, it's not enough to really be effective. Statistical studies from Oxford University have said that it needs 15% of the population for it to be effective, so we are well off that number right now. At the moment, there isn't enough advertising or knowledge of the app. People are also scared about downloading an app from the government, worried for privacy and security. People also fret about battery life, with Bluetooth generally a big drain on battery life, but the app developers have given assurances that it should only take no more than 5% of the battery. 

What may be useful in the future is the check in section, which will allow users to check into stores or restaurants. This may be good way of getting people to download the app as in many places these days, you have to register on a website to allow contact tracing. Telling people they need to download the app before entering the restaurant may be a good incentive for them to use the app. It is mandatory for the stores to produce these QR codes as they face a £1000 fine for not displaying them.

If you do get an alert that you have come into contact with a positive case then you should self-isolate for 14 days. This is meant to be voluntary, though previously the department of health had said that breaking this isolation will mean £1000 fine. It will be hard to ever enforce that though as they will have no knowledge of what has been sent to your phone (due to the de-centralised model).

As a doctor it seems like a good idea if enough people get on board. At work, we have been told to turn off contact tracing due to the fact we will be wearing PPE when in contact with patients. I'll be interested to see how many downloads it gets in the next few months.

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