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The fundamental case against using Bluetooth for Contact Tracing

There is no actual proof that Bluetooth based contact tracing actually works. Even the inventors of Bluetooth say so. So why is no one paying attention to the evidence?
July 31, 2020

"L'informatique est une chose bien trop sérieuse pour être confié à des informaticiens." - (free after Clémenceau)

The fundamental case against using Bluetooth for Contact Tracing:

  1. As far as we know, there is no science connecting the dots between Bluetooth BLE handshake protocols (as used by all Bluetooth apps including Apple/Google) and COVID19 transmission events. No papers, no studies, nothing. We would likely have seen them many times over by now if any existed. Real science requires evidence of effectiveness, not the absence of evidence to the contrary.
  2. None of the countries or states that have deployed Bluetooth based apps are reporting any kind of effectiveness or detection success so far.
  3. None of the countries or states that have deployed Bluetooth based apps are even reporting any kind of reasonable adoption rate thus far. Austria got stuck at 7%. Disciplined Germany was best in class and very proud with its 25% of the country’s 58M smartphone users. If we take that example for 2 people sitting across from each other in a meeting room:  there is a [25% squared] probability that both have the app, assuming it’s operational. That means 6.25%. Times the 72% success rate of the Apple/Google API to detect contact proximity, as measured by the similarly powered app in Ireland. That means 4.5% probability of just detecting presence, nothing more. 95% of the actual transmission opportunities will simply go undetected.
  4. Obviously, the above score is further compromised by the fact that proximity cannot take into account at all the recently “promoted” risk level of aerosol based transmission in small under-ventilated rooms, with air suspended micro droplets lingering for 8 to 14 minutes.
  5. However, of all the contact events that will be detected, only a fraction can be potentially harmful. People across thin office partitions or meeting room walls will be detected, even though there is no transmission opportunity. Meetings outside on a terrace will generate the same contact events, even if the risk is very low. Meetings happening with mouth masks will be detected just the same - no difference. They will all generate false positives and unnecessarily send employees home to quarantine, awaiting the result of their tests in the best of cases.
  6. When testing for proximity in real world conditions, all the adverse effects listed in the article below (*),interviewing both Bluetooth inventors, apply, causing the actual range for the same detected signal strength to vary between 1 and 10 meters depending on surroundings only! There simply is no mapping this onto transmission scenarios. No wonder there is no science.


Articles: Issues with Bluetooth Apps for contact tracing


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