The Centre for Health Protection today said it is investigating a local preliminary positive COVID-19 case from an unknown source involving the L452R mutant strain.

The 41-year-old female patient has been asymptomatic and had no recent travel history.

She worked as a part-time cleaner at Bridal Tea House Hotel, which is a designated quarantine hotel in Yau Ma Tei. She last worked on July 1.

She also worked part-time to provide cleansing service at Bluejay Residences in Ap Lei Chau and House 2, 12A South Bay Road in Repulse Bay where she last worked on June 27 and 29.

She preliminarily tested positive via the regular testing for hotel staff on June 30. 

The centre’s investigation revealed that she had not received a COVID-19 vaccine. 

The Government decided to make a restriction-testing declaration for Port Centre in Aberdeen where she lives, as mutant strains carry higher transmissibility and the risk of infection in the relevant area may be higher.

The declaration took effect from 7.30pm and aims to be finished by about 7.30am tomorrow. People in the area subject to compulsory testing will need to be tested by midnight.

They will need to undergo a nucleic acid test at temporary specimen collection stations set up there, where staff will collect samples through combined nasal and throat swabs.

People in the restricted area who have undergone testing from June 29 to July 1 and can provide a SMS notification through a mobile phone or related certification containing the test results are not required to take the test again.

Meanwhile, any individuals who had been at that building for more than two hours from June 11 to July 1, even if they were not present in the restricted area when the declaration took effect, must undergo compulsory testing by July 3.

In addition, those residing in the same building will also be subject to compulsory testing on the third, seventh, 12th and 19th day counting from the day the case is confirmed.

The patient’s workplaces and the places she had visited during the incubation and infectious period are also included in a compulsory testing notice today.