Can the COVIDSafe app overcome its shortcomings?

False positives, false negatives: can the COVIDSafe app overcome its shortcomings?

False positives, false negatives

Dinesh Kumar, RMIT University and Pj Radcliffe, RMIT University

The Australian government’s contact-tracing app, COVIDSafe, has been touted as crucial for restarting the country’s economy and curbing COVID-19’s spread.

But until more data are collected, it’s hard to estimate how effective the app will be. Nonetheless, there are some predictable situations in which COVIDSafe’s design may mean it will struggle to fulfil its purpose.

False positives
COVIDSafe uses bluetooth to digitally ‘trace’ people with whom a user has come into contact, with the aim of alerting anyone who has interacted with a confirmed COVID-19 case. But this technology carries a risk of ‘false positives’, wherein a user may be falsely alerted despite not actually having come into contact with the virus.

This is because bluetooth radio waves pass through walls and glass. They can only measure how physically close two people are; they can’t tell whether those people are in the same room, in different rooms, or even in different cars passing each other.

In a high-density apartment building, depending on the strength of bluetooth signals, it’s possible COVIDSafe could falsely alert plenty of people.

The Department of Health has acknowledged this complication, saying: "If this happens and one of the contacts is identified as having coronavirus, state and territory health officials will talk to the people to work out if this was a legitimate contact or not."

Nonetheless, this process may cause unnecessary distress, and could also have negative flow-on effects on the economy by keeping people home unnecessarily. False positives could also erode public trust in the app’s effectiveness.

False negatives
On the other side of the coin, COVIDSafe also has the potential for ‘false negatives’ Simply, it will not identify non-human-to-human transmission of the virus.

We know COVID-19 can survive on different surfaces for various periods of time. COVIDSafe would not be able to alert people exposed to the virus via a solid surface, such as a shopping trolley or elevator button, if the person who contaminated that surface had already left the scene.

COVIDSafe is also not helpful in the case of users who become infected with COVID-19 but remain asymptomatic. Such a person may never get tested and upload their contact data to the app’s central data store, but may still be able to pass the virus to those around them. More data is needed on asymptomatic transmission.

And regarding the decision to classify ‘close contacts’ as people who have been within a 1.5m distance for 15 minutes – this may have been based on research from Japan for when people are in an open space, and the air is moving.

However, this research also showed micro-droplets remained suspended in the air for 20 minutes in enclosed spaces. Thus, the 1.5m for 15 minutes rule may be questionable for indoor settings.

Downloads vs usage
Recently, Iceland’s contact tracing app achieved the highest penetration of any such app in the world, with almost 40 per cent of the population opting in. But Icelandic Police Service detective inspector Gestur Pálmason – who has overseen contact tracing efforts – said while it was useful in a few cases, the app “wasn’t a game-changer”.

Australia’s Prime Minister Scott Morrison has said on multiple occasions COVIDSafe requires a 40 per cent uptake to be effective.

Since then, federal health minister Greg Hunt has said there’s “no magic figure, but every set of people that download will make it easier and help”. This was echoed more recently by Department of Health acting secretary Caroline Edwards, who told a Senate committee there was no specific uptake goal within her team.

Past modelling revealed infection could be controlled if more than 70 per cent of the population were taking the necessary precautions. It’s unclear what science (if any) was forming the basis of Australia’s initial 40 per cent uptake goal for COVIDSafe.

This goal is also lower than proposed figures from other experts around the world, who have suggested goals varying from 50-70 per cent, and 80 per cent for UK smartphone owners. But the fact is, these figures are estimates and are difficult to test for accuracy.

A survey conducted by University of Sydney researchers suggested in Sydney and Melbourne, COVIDSafe’s uptake could already be at 40 per cent – but lower in other places. Shutterstock

Demographic bias
There are many other uncertainties about COVIDSafe’s effectiveness.

We lack data on whether the app is actually being downloaded by those most at risk. This may include:

We also know COVIDSafe doesn’t work properly on iPhones and some older model mobile phones. And older devices are more likely to be owned by those who are elderly, or less financially privileged.

What’s more, COVIDSafe can’t fulfil its contact tracing potential until it’s downloaded by a critical mass of people who have already contracted the virus. At this stage, the more people infected with COVID-19 that download the app, the better.

A tough nut to crack
Implementing a contact tracing app is a difficult task for our leaders and medical experts. This is because much remains unknown about the COVID-19 virus, and how people will continue to respond to rules as restrictions lift around the country.

Predictions of the disease’s spread have also shown a lot of variation.

Thus, there are many unknowns making it impossible to predict the outcome. The important thing is for people to not start taking risks just because they’ve downloaded COVIDSafe.

And while the government pushes for more downloads and reopening the economy, ongoing reviews will be crucial to improving the app’s functionality.The Conversation

Dinesh Kumar, Professor, Electrical and Biomedical Engineering, RMIT University and Pj Radcliffe, Senior Lecturer, Electrical and Computer Engineering, RMIT University

This article is republished from The Conversation under a Creative Commons license. Read the original article.

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    To make a comment, please register or login
    Pass the Ductape
    20th May 2020
    What's the bet it''ll turn out to be nothing a big white elephant!
    The Thinker
    20th May 2020
    Of course, it will.
    20th May 2020
    I don't think anyone claims the app will be perfect or won't have all the drawbacks mentioned. But this is early days in a very new ballgame, and the app is only one tool in an arsenal of weapons, all similarly in the early stages, for fighting this virus. People just need to get on board, download the damn thing and forget it after that... unless you get contacted about it, or unless you are confirmed to have the virus from other sources.
    The Thinker
    20th May 2020
    Instead of monitoring people and trying to get rid of the cash economy, people want a cure.

    Doing business with a Dictatorship that has abused human and animal rights has never been good for Australia.
    The Thinker
    20th May 2020
    I am not interested in downloading the App. Get a cure instead. Stop selling iron ore and our land to China. Create Australian industries instead of making Australia a vulnerable target for a non-Allie such as China.
    20th May 2020
    Oh for goodness sake. Its a tool nothing more! And we simply cannot rely on 70% of peopole doing the right thing 100% of the time. They won't!
    20th May 2020
    Spot on :)
    20th May 2020
    The Downloaded COVIDSafe app my concern!

    The app will not stay live!!
    No matter how many times I switch on the App it self switches itself off

    I will add I do switch from WIFI to Phone data and reverse but when I first noticed the app was not running I looked to make sure the app was live on each switch over

    I have not seen anywhere for ‘help’ on the COVIDSafe App

    I have received an answer see below but am still skeptical on its operation.

    Thanks for your email. From what I can see if you have bluetooth turned on, you shouldn't have any issues

    Let me know how you get on

    Best, "Life Choices"
    20th May 2020
    The apps claim of providing protection with criteria of 15 minutes at 1.5m is as effective as police provided with speed detecting radar set at at steady 89km per hour for 3km and then claiming that its caught everyone speeding. You may be infected in a one second sneeze in your direction at 3m. The app doesn't work and it won't work to any useful extent. This is a government attempt to look like it's doing something and maybe to test the public's acceptance of future tracing apps. You'd probably be equally well protected sitting under a mosquito net.
    Pass the Ductape
    21st May 2020
    Fantastic! Another person able to see through the current hype, then, attempting to alert people to a future where 'big brother' will undoubtedly use the knowledge gleaned from this experiment to further the need for total control of 'his' subjects!
    21st May 2020
    We know all ifs and buts that but you are not helping.
    This app gives people the confidence to come out from under the doona.
    It may help tracing especially for people who have forgotten where they have been. The more people who have the app downloaded the more people who can be alerted before it spreads.
    Please stop sabotaging Plan A.
    Pass the Ductape
    21st May 2020
    Yes....on the face of it, it's fair call Rosret, but we still need to be very aware of what we wish for.
    You obviously have a lot more faith in the Governments 'good' intentions' than I have, but then I might have been around a little bit longer.

    Going on past experiences - I wouldn't trust the bastards for one second - particularly on something as intrusive as knowing an individuals where-a-bouts every second of the day.
    21st May 2020
    Rosret, yes that's a really great idea, encourage people to put faith in a device that's about as ineffective as a can of Mortein in a locust plague. The app is statistically ineffective in most situations.
    21st May 2020
    Where are you Greg!. Being silent doesn't help your idiotic comments!

    The bullshit Covid-19 safe App as I call it has been fully dismantled by the article above as no more than a big brother tool. I'm amazed Dan Andrews has fallen for the Morrison Crap (who by the way has repeatedly been shown to be a scientific illiterate like Trump) because it suites the LNP political game of appearing to do something, but in fact may be doing more harm than good.

    Like I said, on the surface for the App to be legally acceptable, it must not disclose the owner's whereabouts at the time its Bluetooth alert interacts with other Bluetooth devices nearby. Please explain how it's possible to trace a connection if party A can't remember where they've been a week previously and been close to Party B if the App can't say where the contact was made? This is assuming Party A doesn't know Party B from a bar of soap.

    Also Party A must be at least 1.5 metres away from Party B or closer. What about Party A meeting Party B and forming a relationship? is this now banned?

    What about if Party B doesn't like washing hands properly and touches something like the outside of a paper dispenser and leaves Covid 19 bug (which can survive up to 48 hours) on the surface and Party A touches it the next day and becomes infected. Where is the App then, by the next day Party A and Party B could be hundreds of miles apart, like if A lives in Epping and B lives in Rosebud or Geelong. The Bluetooth App wouldn't work period. Even if it did, how many Party A's will get infected in the meantime that the App will miss altogether? If then Party A went for a test after 2-5 days and found positive, Party B is also positive, but can't remember washing their hands in a public toilet somewhere in the CBD about 10 days before, nor can Parties C,D,E,F............Z.

    So, as much as contact with the virus can become exponential, the reverse happens with the App not reporting expanding clusters.

    Like I said many times in previous posts, the App must record the location of where contact was made, thereby blowing your assurance by government of privacy out of the water. Don't be fooled, of course the App records your whereabouts at all times, but it can't be stated publicly because this is legally a no-no under the Act and Regulations as we have been led to believe.

    Can Greg get off his high horse and explain?
    21st May 2020
    This report highlights some of my concerns about the technology. First how can Bluetooth differentiate between a near contact that is less than the 1.5 metre away and a contact over 15 meters away. Probably it can't. How can it be guaranteed that the Bluetooth signal will extend up to 1.5 metre., In particular situations, say a crowded public transport vehicle or a lift, most of the signal will be absorbed by human bodies. I know with 'social distancing' this should not happen but if people start going back to work how are number of passengers on each vehicle going to be controlled. Who is going to volunteer to stand on a draughty railway platform or bus stop waiting, possibly for hours, for a 'non-crowded' vehicle to arrive? Bluetooth works by 'pairing'. With all the myriad of Bluetooth signals in the ether two devices have to be paired to respond to each other. If this app has found a way to countermand his pairing why cannot hackers? Can this possible vulnerability be exploited to gain access to a personal data on a phone? Is this reliance on technology have more cons than pros? Fortunately for me this is a non-issue as my $49 phone does not support Bluetooth.

    Tags: covid 19, app,

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