The COVID Alert Malta app will become interoperable with those of other EU Member states in the coming weeks, this newsroom is informed.

Back in September of 2020, the government launched a contact tracing app under the name ‘COVID Alert Malta’ with the aim of reducing the health authorities’ workload of following a spike in cases towards the end of Summer.

It was developed by the Malta Information Technology Agency (MITA) and the Malta Digital Innovation Authority and over 45,000 people downloaded it in the first two days of it being launched.

Nonetheless, the rate at which it was being downloaded started to decrease bit by bit with the number of downloads doubling just this month. During last Friday’s Covid-19 press briefing, the Superintendent of Public Health Prof Charmaine Gauci indicated that only 19% of the population (91,215 people aged 13+, that is, the age of digital consent).

The Malta Independent spoke with the health authorities to get a better idea of how the app works and its usefulness as the vaccine starts to be rolled out.

‘Any slowdown would relieve pressure on the government health services’

When asked to indicate how useful the app has been in catching out positive cases, the health authorities said that since 14 November 2020, the Covid-19 Public Health Response Team has been voluntarily notified 1071 times (up until 11 January 2021) by individuals who were informed by the COVID Alert Malta app to seek testing.

“The app continues to be a relevant and important tool in the fight against the Covid-19 pandemic,” the health authorities remarked when asked if the app will be losing its effectivity now that the vaccine is being rolled out.

They noted that that even if the uptake of COVID Alert Malta ends up being limited, the app has still contributed to slowing down the epidemic, especially in combination with the other measures implemented by the government.

“Any slowdown would relieve pressure on the Government health services and help a higher proportion of patients receive proper care, potentially saving many lives. A slowdown would also buy time until we fully transition to herd immunity.”

The authorities added that, in the coming weeks, COVID Alert Malta will become interoperable with those of other EU Member states, therefore the app will soon play a role in preventing spread among persons who wish to travel between EU countries.

App is completely anonymous, based on randomized codes

COVID Alert Malta’s exposure notification system aims to alert users when they have been exposed to a potentially infectious user using proximity tracing. It records certain data, like the time spent near other people who also have the app, and the distance between the persons.

The only downsides of the app are that the user must keep their devices’ Wifi and Bluetooth on at all times in public spaces for it to work and that it cannot be downloaded on certain old phones which use outdated operating systems.

However, it is important to note is that the use of the app is completely anonymous as it does not collect any personal data, including the places visited.

If the app detects that you have been in close proximity to someone who tests positive, it will send an alert and urge the person to call the 111 helpline.

Here is a simplified explanation of how the system works through the example of two hypothetical users, Mario and Roberta:

Roberta installs the COVID Alert Malta app from the Google Play Store or Apple App Store. Her smartphone starts sending a Bluetooth Low Energy signal that contains a random code and it does this on a continuous basis. The same goes for Mario.

When Roberta and Mario are in close proximity, their smartphones mutually store each other’s random code, taking note of that event. Their phones also note how long the event lasted and the approximate distance between the two devices.

The codes are generated randomly, and they do not contain any information about the user or their device. They also change several times each hour, protecting user privacy even more.

Let’s suppose that Mario later tests positive. He will be provided with a code by the Public Health Department that he can voluntarily enter in his smartphone. When Mario does this, the app will transfer some cryptographic keys (secret codes) to a server. From these keys, it is possible to derive Mario’s random codes that were broadcasted during the time he was potentially infectious.

For each user who has the COVID Alert Malta app installed, the app regularly downloads all the new cryptographic keys sent to the server by those users who tested positive for the virus and entered their code in the app. The app uses these keys to derive their random codes and checks if any correspond to those stored in the device’s memory in the previous 14 days. For example, Roberta’s app will find Mario’s random code (without knowing that it is Mario’s) and will notify Roberta that she was potentially exposed to the virus.

Up until last Friday, 505 codes were given to people and 305 of them inputted the code to alert those who might have been in close proximity to them, putting Malta in second place with regards to the effectiveness of the app.

Exposure must last for more than 15 minutes at a distance of less than 2 meters for a person to be notified

This newsroom asked the authorities whether everyone that comes into contact with the positive case has to quarantine, even passers-by.

Notably, COVID Alert Malta uses the Received Signal Strength Indicator (RSSI) measurement values of signal strength between the phones. RSSI calibrated values are used to estimate the approximate distance between users, while the duration of such a connection is recorded by the mobile application itself.

When two smartphones on which the app is installed are within a few metres of each other, they start exchanging random codes to record that contact took place. However, this is not enough for someone to be notified of a risky exposure if their smartphone recorded contact with a user who later tested positive for the virus.

For a person to be notified, the following conditions need to apply.

Firstly, the user who tested positive for the virus must have uploaded their cryptographic keys to COVID Alert Malta’s server to enable the notification of the users to whom they have been exposed.

Additionally, exposure must have taken place for more than 15 minutes at a distance of less than 2 metres, as established by the Ministry for Health.

More information and frequently asked questions about the app can be found here.