Authorities said the case involves a 50-year-old man whose infection was identified through mandatory testing at Hong Kong International Airport, after an airline ground crew member was infected two weeks ago.
The new patient is a porter at the airport who mainly performed duties at the apron, and he last went to work on Saturday.
He received the first dose of the BioNtech vaccine on July 1 and has been asymptomatic, but was found to carry the L452R mutant strain.
Officials said the latest patient doesn’t know the previously infected airport worker.
The building where the man lives at 1-3 Kam Fung Street was cordoned off at 7:30 pm, and residents were required to undergo compulsory testing before midnight.
“The risk of infection in the relevant area is assessed to be likely higher, so the government decided to make a ‘restriction-testing declaration’ for the relevant area after the test result was found positive,” a government spokesman said.
Officials said they aim to finish their operation by around 7 am.
The airport and places the man visited will be included in a compulsory testing notice.
Earlier, the Centre for Health Protection reported an imported Covid case, a 16-year-old boy who had flown in from the UK.
He was in quarantine at a Hung Hom hotel, when he tested positive for the virus.
He did not have any symptoms.