A lot of people are promoting the idea of using the COVIDSafe app, but its efficacy is likely to be weak and it won't stop you from getting sick, only help prevent you spreading to others. Current hygiene, social distancing, testing and contact tracing are likely to be the most effective way to stop this epidemic.

To successfully trace a contact using the app, all people in the space need to

• be there at exactly the same time
• have the app installed
• have the app properly set up,
• phone needs to have charge
• a successful bluetooth exchange needs to happen and
• the person who is infected needs to be tested.

That is a lot of things that need to go right.

The app will not be able to detect:

• when you walk through an area that an infected person has recently walked through
• when you touch a handrail a few minutes after a person who is infected has touched it
• if any of the people being contact traced have the app working properly

The people you are most likely to infect are the people you are most in contact with. So your work colleagues, classmates, and family, all of which you can get near 100% contact traces for. And as for travel, if you happen to jump on a bus with an infected person, that person's travel card can be used to determine the bus number and then all the people who got on after them, with near-100% accuracy. It is unlikely that the COVID-19 app will match that level of accuracy, especially if only 40% of people install the app.

So doing social distancing, good hygiene and testing should still be front of your mind.

I am a cynic when it come to the government and privacy. Yes, Greg Hunt made a legislative instrument outlining what should or shouldn't be done with the data. Meanwhile, the Assistance and Access Bill still allows the government to compel companies to add backdoors to apps and makes it illegal for the company to complain publicly about it. It is not clear from a legal standpoint that Greg Hunt's legislative instrument overrides the Assistance and Access bill.

That said, I don't believe the app adds greatly to the security risk of individuals who use it (the government can currently compel Google or Apple to reveal your entire travel history without the COVIDSafe app).

So I don't recommend that you should use it, but I also don't recommend that you shouldn't. Just keep up the good work, Australia!