ACT Health is continuing to investigate how two returned travellers in hotel quarantine in Canberra acquired COVID-19, with authorities believing they contracted the virus in transit from overseas.

Two close contacts of the men outside the returned travellers’ cohort have been identified and are in quarantine. Both contacts have returned a negative COVID-19 test result.

The two returned travellers, who are not related, are being supported in a separate area of the hotel, ACT Health says.

The younger of the two cases, a male under 20, is quarantining with two other family members.

ACT Health says contact tracing work will continue over the weekend, however it “remains likely” the infections were picked up in transit.

“ACT Health is continuing to liaise with NSW Health authorities and Singapore Airlines about the two cases to support other contact tracing efforts.

“Genome sequencing testing is also ongoing to determine if these individuals have been infected with a variant strain of COVID-19.”

Additional testing of the other returned passengers in hotel quarantine has been organised, with testing to take place on day five of the quarantine period. At this stage, no other returned travellers have reported symptoms of COVID-19.

“This will help identify any further cases early during the quarantine period so we can respond quickly.

“Any returned passenger experiencing any symptoms of COVID-19 at any point during the 14-day quarantine period will also be tested.”

The latest update comes as the ACT Government prepares to make its contact tracing app, Check In CBR, mandatory for restricted businesses from tomorrow, Saturday 6 March.

The ACT Government has a dedicated COVID-19 website for local information: covid19.act.gov.au