The five buildings are:

- Block 3, Phase 1 of City Garden in North Point;

- Block C of Pik On House, Yue On Court in Ap Lei Chau;

- Fung Fai Terrace in Happy Valley;

- Mei Sun Building on Kau Hui Chik Street in Tai Po; and

- Kam Fung Court on Sai Sha Road in Ma On Shan.

The lockdown in North Point, Ap Lei Chau, Happy Valley and Tai Po are expected to be lifted at 7am Friday, while the one in Ma On Shan at 8am.

Vaccinated residents are required to undergo the testing as well. Only those who had tested negative between Tuesday (Jan 4) and today (Thursday) with relevant proof could be exempted from taking the test again.

The compulsory testing requirement also applies to citizens who had been to the three buildings in North Point, Ap Lei Chau and Tai Po for more than two hours between December 30, 2021 and today, as well as those who had been to the Happy Valley block between December 28 and today.

Those who been to the Man On Shan block between December 29, 2021 and today should also take the Covid test.

They must all undergo compulsory testing by Saturday (Jan 8).

The residential building in North Point was locked down due to a 73-year-old retired woman who tested positive. She had once danced with the Cathay flight attendant's mother at Causeway Bay Community Center on December 31, 2021.

She was sent to the quarantine center on Tuesday and tested preliminary positive for the coronavirus on Wednesday. She developed symptoms and was admitted to a hospital on Thursday.

As for the lockdown in Happy Valley, it was triggered by a 67-year-old woman who had dined with 14 dancing friends, seated at two tables, at Wealthy Garden in Causeway Bay on New Year's Day.

The Tai Po residential block was locked down after an Indonesian domestic helper tested preliminary positive. The helper had contact with an infected domestic helper – who works for a friend of the flight attendant's mother's – in a Mong Kok church on January 2.