HONG KONG - The Hong Kong government on Friday night cordoned off a building in Happy Valley after a preliminary positive COVID-19 case involving the mutant strain was detected in the area.

A restricted area was set up at Way Man Court, 50-52 Village Road in Happy Valley at 7:30 pm after a 31-year-old foreign domestic helper tested preliminarily positive for L452R mutant strain.

Residents of the building were required to stay in their premises and undergo compulsory testing before 11 pm Friday. 

She (the patient) underwent another test on Nov 18 at a community testing center and the sample tested preliminarily positive, with a low viral load, a Ct value of larger than 30.

Centre for Health Protection

As of around 11 pm, around 130 residents had undergone testing. No confirmed cases were found. The enforcement operation ended at around 8:45 am Saturday.

The government said it had assigned staff to visit around 50 households, among which around five did not answer the door. It added that it would follow up on the matter.

In a statement issued Friday evening, the Centre for Health Protection said the patient arrived in Hong Kong on Oct 23 from the Philippines on Cebu Pacific flight 5J272. Her specimen collected upon arrival at Hong Kong International Airport tested negative for COVID-19. 

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The results of six tests conducted during her compulsory quarantine at Penny's Bay Quarantine Centre were also negative. Upon completion of the compulsory quarantine on Nov 13, she returned to the residence of her employer at Way Man Court. 

"She underwent another test on Nov 18 at a community testing center and the sample tested preliminarily positive, with a low viral load, a Ct value of larger than 30," the CHP said.

Her specimen carried the L452R mutant strain but was negative for the N501Y and E484K strains, the center added.

She has been asymptomatic and received one dose of Janssen vaccination on July 23 in the Philippines. 

"One of her test results after admission to hospital was indeterminate while her antibody test was positive," the center said.

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Due to the presence of a mutant strain, the government has decided to declare the building where she lives as a restricted area.

The places where she has visited in Hong Kong during the incubation period will also be included in a compulsory testing notice, the center added.