Ministry of Health has not used bluetooth data to contact trace

Andrew Chen writes:

We know that contact tracing is a critical part of our ability to contain any outbreak of an infectious disease. Bluetooth Tracing, offered through the NZ COVID Tracer app, is part of that process in New Zealand. Or at least, it should be. Technical folks over the last week have noticed that the most recent Bluetooth data made available to the NZ COVID Tracer app was on 17 August – the day we found out about Case A with the delta variant and the country went into lockdown. No Bluetooth keys have been uploaded to the central server since then, despite there being 512 positive cases at the time of writing. This therefore means that there have been very, very few Bluetooth-based exposure alerts sent to users. So why is there no Bluetooth Tracing data when there have been many Locations of Interest and related alerts sent out for QR code-based locations?

And the answer is:

Questions about the lack of Bluetooth keys have been put to MOH over the course of the last week, by myself and other members of the public, as well as by a number of journalists who have also asked me for comment. MOH has not provided a clear, defendable answer until the 1pm press conference on 29/08, when in response to a journalist question, Bloomfield pointed to the contact tracers not asking for Bluetooth information at the first case interview due to the number of cases, and also the demographic groups of the cases being less likely to use BT. He also claimed that “we have been using it where people have said they have Bluetooth turned on, and we’ve used that to send out messages,” but we know based on the MOH server that this has actually only happened for Case A. He added “we have given [the contact tracers] a nudge around that.”

I thought a lot about whether to write this article or not, because anything that might cause people to stop using NZ COVID Tracer is counterproductive in the age of delta. But MOH has had long enough to respond to queries and be upfront with the public about why Bluetooth isn’t being used. New Zealanders have been asked time and time again to “turn Bluetooth on”, and I have spent a lot of time trying to explain how it works, how to turn BT on, and why people should use it. It is frustrating to see the data potentially isn’t being used to support contact tracing. If, as I suspect, the explanation is that contact tracers simply aren’t asking for the information, then we need a policy decision as to whether this system is actually useful for contact tracing. If it is useful, then the contact tracing processes need to be amended to ensure that they are asking for BT information. If it is not useful, then we can have a different debate. Either way, this is about making sure we not only have the right tools to help us fight the virus, but that we are using them effectively.

This is pretty staggering. Basically the Ministry of Health has not trained contact tracers to ask if an infected person has used the bluetooth function. Considering the mounds of advertising on the capability, and how we were told it was vital people turned it on, this is hugely disappointing.

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