Why decentralised tracing is wrong.

14 05 2020

Let me be clear, I am not associated or working on any tracing app. I am a user. Let’s also be clear. Covid-19 is a frightening virus which has a horrible impact on some. 30% of patients dont make it out of ICU. The impact on some ethnic minorities is disproportionate. If you have a BMI over 30 your 37% more likely not to survie.

Our aim as a society is to eliminate it. Every tool available needed in this fight, and technology is one of those tools. I an ideal world, every person would have the latest mobile device, with the latest OS. They would always have the device turned on and operating. When they became ill they would self diagnose with 100% accuracy and honestly report to the app which would dutifully report to all contacts. The world is not ideal, its messy and imperfect. Covid-19 jumped into humans. Most people even in 1st world countries don’t have a mobile device that will run the app. (evidence, Isle of White, 80% of vulnerable people (elderly) and poorer families have old iPhones pre iOS 10. I much smaller number have Android pre 6.0). The population are not clinicians and they are scared. They will over report, misdiagnose and even in rare cases maliciously report. In Germany, the decentralised app requires evidence of a positive Covid-19 test to combat this. In Germany that combats the incorrect reports, as Germany has a surplus of testing capacity. In other countries (eg UK, probably US) health care and social care workers struggle to get tested.

Technology for tracing is an assistive tool, but must augmented by other techniques. Without centralised anonymised data, it is impossible to perform any of the other standard epidemiological processes that eliminate the spread of infections. Most countries have done this for years on a small scale ensuring that sexually transmitted diseases have not become pandemic.

When a parent, who doesn’t drop their primary school child at school becomes ill and notifies the decentralised tracing app who will tell the school. Who will tell the parent of other children in the same class at the school. Who will tell the care homes where the parent of the other children in the same class at the school that look after the 85 year old loved grandparents, none of whom anywhere in that chain had a mobile device capable of running the app notified by some decentralised method that knows nothing about humans and the messy world we live in.

In the centralised tracing model, the team of human tracers have access to that information and will phone the school, get the list of parent, warn them to self isolate. The few Covid-19 tests that are available will be used by the social care workers and hopefully they won’t infect the 85 year old loved grandparents.

In addition because we said, this is different, this isn’t about a miniscule and irrelevant risk to privacy but about the lives of my loved ones, the health organisations we believe in and trust have the data they need to protect us all. We unknowingly give far more personal tracking data to internet giants in return for being recommended 2m videos of almost no relevance. Of course Apple and Google want to force us to use the decentralised model. They don’t want their credentials for protecting privacy to be questioned. The mechanisms in use drive their business models. And they don’t care if you don’t have a phone you can’t run it on, your not a customer. Decentralised tracing only protectects wealthy Apple customers. Google is better, a 10y old Google Nexus will run the UK NHS App.

It reminds me of when Apple¬† or Google (can’t remember which) developed some AI for a health feature but couldn’t understand why it was reporting health conditions monthly for just over half the population between the ages of 14 and 50, until the one woman in the meeting asked if there were any females in the set of training data. Dumb mistake. Period.¬† Not realising the world is real is a big mistake to be making again.