PETALING JAYA: Staying at home all day and yet still finding your MySejahtera’s MySJ Trace showing that you have interaction?

Fret not. This is because the Bluetooth signal can be detected up to 10m away, said Dr Mahesh Appannan, head of data at the Crisis Preparedness and Response Centre.

“Maybe your handphone is detecting your neighbours’ (Bluetooth signal), including those on different floors and nearby in an apartment.

“However, this doesn’t mean you straightaway become a casual contact, as the app’s algorithm takes into account the signal strength that varies according to hindrance,” he said on his Twitter.

Dr Mahesh was responding to a Twitter user who asked why her MySJ Trace showed her having eight interactions when she was at home, while her parents have yet to activate the feature.

MySJ Trace is a feature that uses the phone’s Bluetooth function to provide live tracking of interactions between users, subject to the user’s access permission.

It is meant to help with detecting close contacts in the case of a Covid-19 outbreak to control the spread of virus infection.

Dr Mahesh also assured that all user data are not shared or compromised while using MySJ Trace, as the data would only be stored in the user’s mobile phone.

He said users will only be asked to share the data of their history of up to 14 days if they are Covid-19 positive, so that notifications can be sent to those considered as close contacts.

“And this needs explicit consent,” he said.

If one is not Covid-19 positive, he said the data will not be uploaded and would be deleted after 14 days, he said, adding that the same mechanism was used in the UK and Singapore.

On why the need to use the check-in feature apart from MySJ Trace, Dr Mahesh said that the latter, which only requires activation, emphasise personal data sharing and not everyone is using it.

He said the MySJ Trace function also analyses distance between users, based on the Bluetooth signal strength.

“The combination of MySJ Trace and check-in enables automatic contact tracing, in a way that ensures data privacy while generating data critical for the public health team at the Health Ministry,” he added.