Category Archives: Public Health/Coronavirus

coronavirus apps do not need 60+% adoption to be effective 

A meme has been established that smart phone contact tracing apps need at least 60% adoption to provide any benefit. That is not the correct interpretation as their could be detections at lower adoption levels, and if you detect anyone, then that is defined as a “benefit”, albeit, it may be a very small benefit – such as detecting one or two potential contacts, which is probably not sufficient to make any difference in disease spread.

MIT Technology Review cites Iceland as an example of 40% adoption rate and suggests this is a “significant level of adoption”.

Uhhh, no, and the source they cited to make this claim actually says the app “hasn’t helped much”.

Continue reading coronavirus apps do not need 60+% adoption to be effective 

UK’s NHS tried to stop development of third-party contact tracing smartphone apps

The UK has since abandoned its NHSX developed app and is now moving on to a new app based on Google/Apple tech, but is not expected to release the new app until … end of 2020:

Developers of several apps were urged to stop work by either NHSX or the Ministry of Defence, who told them their apps might distract attention from NHSX’s app when it was launched. Last week the app was abandoned after three months, with work beginning on an alternative design without any deadline.

Prof Tim Spector, of King’s College London, said that NHSX had treated his Covid symptom tracker research team as “the enemy”. “We were hampered from the beginning, in March when we first contacted NHSX,” he told the Observer. “They were very worried about our app taking attention away from theirs and confusing the public.

Source: NHS Covid app developers ‘tried to block rival symptom trackers’ | Technology | The Guardian

Adoption of contact tracing app in France off to a very slow start

France was one of the first Western countries to build an app to track exposure to the coronavirus, but sluggish takeup rates could limit its usefulness in preventing a second wave.

Source: French Contact-Tracing App Struggles with Slow Adoption. It Isn’t Alone – WSJ

What many do not understand is that it requires a lot of people to have a smart phone and to install and use the app for a phone to detect potential coronavirus exposures.

To illustrate – in most modern countries about 80% of adults have a smart phone (plus or minus). When we adjust the figure for young kids who do not have a smart phone, about 2 in 3 people have a smart phone or 63%.

If half of all smart phone users install a contact tracing app, then we have about 32% have the app. In order to detect a contact, you need to be close to someone else with the same app. The probability of that occurring is .32 x .32 or 10%. Thus, what seems like wide spread adoption yields a potential of detecting just 10% of possible Covid-19 contacts.

And this probability does not take into account the problems with contact tracing apps:

  1. Incapable of detecting contacts across time (someone sits on a bus seat, coughs, gets up, leaves, and then you sit there)
  2. Difficulties with multi-path radio signals that result in false signal strength readings (this is common)
  3. Incapable of detecting when there is a barrier between contacts. For example, you are on a bus stopped at a bus stop while the driver takes a break. Someone with Covid-19 standing outside the bus results in alerting your phone that you just had a contact. Except you really did not due to the physical barrier.

UK’s NHS Covid-19 contact-tracing app postponed until next winter

Their Isle of Wight trial taught them several things – and the UK has now postponed the roll out of a smart phone contact tracing app until probably the end of the year.

Minister says smartphone tool was not a priority for the government at the moment

Source: NHS Covid-19 contact-tracing app for UK will not be ready before winter | World news | The Guardian

Japan pulls its coronavirus tracking smartphone app due to software design errors

The Japanese government has pledged to fix within a week bugs that have caused its coronavirus contact-tracing smartphone app to be shut down, the health minister said Tuesday.

The free app, which was launched Friday and downloaded around 3.71 million times as of Tuesday morning, erroneously accepts ID numbers not issued by the Health, Labor and Welfare Ministry, Katsunobu Kato, the minister responsible for the system, said at a press conference.

Source: Bugs force Japan gov’t to temporarily shut down virus contact-tracing app

UK smart phones display feature update for contract tracing – but its confusing as its not actual contact tracing

Update: The UK government terminated its contact tracing app trial, on going since the beginning of May and will now develop a new contact tracing app based on the Google/Apple Bluetooth tech.

More confusion and incoherent messaging in the public health domain:

A Covid-19 tracing software tool has appeared in the settings of both Android phones and iPhones as part of an update of their operating systems.


In the UK there is currently no available contact-tracing app.

The update has caused some confusion, with people querying the new addition to their handsets on social media.

Source: Coronavirus: New Covid-19 tracing tool appears on smartphones – BBC News

Sounds like the UK is starting over. Their original app used a central cloud-database and now they will develop an app based on the Bluetooth, no-cloud storage model.

Australia’s Bluetooth-based contact tracing app deemed largely irrelevant

Says they’ve identified a total of … one person:

The PM told Australians in April the contact tracing app was key to getting back to normal but just one person has been identified using its data

Source: How did the Covidsafe app go from being vital to almost irrelevant? | World news | The Guardian

Remember, Singapore pulled their Bluetooth app. Norway used both Bluetooth and GPS and pulled their app for EU privacy problems. The UK’s been testing their Bluetooth app on the Isle of Wight – was supposed to have gone nationwide more than a month ago but since then, things have gone quiet.

UK expected to drop 6-foot / 2 meter social distancing rule, possibly replace with 3-foot / 1 meter distancing

Pretty much everyone in the world except North America, Spain and the U.K. have used WHO’s recommendation of a 3 foot / 1 meter spacing up to 1.5 meters, but not 2 meters:

My wife is a retired R.N. and noted the 3-foot / 1 meter spacing was a common distance used in health care.

It is a total mystery: Oregon Covid-19 cases rise sharply since May 28th

Definitely, absolutely, positively not related to mass super spreader protest events starting May 28th, where participation was recommended by public health enthusiasts – but we really do not know anything at this point.

Public health officials are struggling to discern how Oregonians are being exposed to the virus. According to the latest data, for the week June 8-14, contact tracers were unable to identify the source of infection for 36% of new cases statewide. In the Portland area — encompassing Multnomah, Washington and Clackamas counties — it was even worse: 48%.

Source: More Oregonians catching coronavirus because the virus is spreading more, not just because of increased testing –’

Continue reading It is a total mystery: Oregon Covid-19 cases rise sharply since May 28th