Covid-19: Govt launches mobile app which can speed up contact tracing by detecting nearby phones with app installed

SINGAPORE — A new mobile application launched by the Government on Friday (March 20) aims to speed up contact tracing efforts by the authorities during the Covid-19 pandemic by detecting and recording nearby phones that also have the app installed.

The app, created by the Government Technology Agency (GovTech) in collaboration with the Ministry of Health (MOH), is called TraceTogether and works by exchanging short-distance Bluetooth signals between mobile phones that have the app installed.

The app estimates the distance between the users and the duration of their contact, and this information will be recorded and stored locally on each user’s phone.

The app’s detection range depends on the user’s phone type, but the data will help MOH determine who was within 2m of the user and if they were within that range for at least around 30 minutes, a spokesperson from GovTech said during a technical media briefing on Friday.

The 2m distance and 30-minute time bracket are the parameters set by MOH to initiate contact tracing.

If either user is later interviewed by MOH as part of contact tracing efforts, the user can then consent to send the TraceTogether data to the ministry.

Using the data, contact tracers would then be able to quickly establish the identities of the people with whom the person had been in close contact recently and could then contact those people, too.

MOH and the Smart Nation and Digital Government Office (SNDGO) said in a joint statement: “Currently, contact tracing relies on the recall and memory of interviewees. There were, however, instances when interviewees could not remember all their contacts, or did not have information on whom they had been in contact with. 

“This enables users to take the necessary action sooner, such as monitoring his own health closely for signs of flu-like symptoms. Early detection could potentially help reduce the risk of the spread of the virus, and better protect our families and loved ones.”

At the media briefing, an SNDGO spokesperson said the tool is “not 100 per cent” even if everyone downloaded the app, because some people might forget to carry their phone on a given day.

There is no “magic threshold” but if a person is able to identify 25 per cent to 50 per cent of their contacts by using the app, then this would help the contact-tracing team.

PRIVACY CONCERNS

When users first download and set up the app, they will have to give explicit consent to participate in TraceTogether and agree to have their mobile number and TraceTogether data used for contact tracing.

Only a person’s phone number is needed for verification at the set-up stage and no other personal particulars are collected.

Up to the point MOH requests the data and users send it to the authorities to facilitate contact tracing, the authorities would have no knowledge of the user’s TraceTogether data, MOH and SNDGO said.

“The TraceTogether logs are deciphered and analysed only after the user sends the information.” 

All logs are stored locally on the user’s phone in an encrypted form for 21 days, thus covering the incubation period of the virus, and they do not contain the users’ phone numbers but a set of cryptographically generated temporary IDs.

And these logs leave the user’s phone only when he or she provides authorisation for the information to be sent to MOH for contact tracing.

MOH will then decipher the data and get the mobile numbers of the user’s close contacts within a period of time.

If the user did not come into close contact with any reported Covid-19 patient, TraceTogether data older than 21 days will be automatically deleted.

TraceTogether does not collect or use location data of any kind, and does not access a user’s phone contact list or address book.

“TraceTogether enables each of us to be socially responsible and play a proactive role in helping to contain the spread of virus in our community through effective contact tracing,” MOH and SNDGO said.

SNDGO will work with both the public and private sectors to raise awareness and encourage adoption of the app.

WHAT USERS HAVE TO DO

Step 1: Download the TraceTogether app or to go www.tracetogether.gov.sg.

Step 2: Enter their Singapore-registered mobile number.

Step 3: Provide consent to register their numbers with TraceTogether and consent to also share them with MOH if users are identified as either a confirmed Covid-19 case, or a close contact of a known case.

Step 4: Turn on Bluetooth and enable the necessary permissions for TraceTogether to function. Keep push notifications turned on, so that users can be notified when their Bluetooth is switched off unintentionally.