(To watch the full press briefing with sign language interpretation, click here.)

The Centre for Health Protection today said it is investigating 16 additional COVID-19 cases and urged citizens at high risk to undergo viral testing given the increasing number of cases with unknown infection sources.

The newly reported cases consist of nine imported and seven locally infected, with the source of infection of two cases still unknown.

One of the unlinked cases involves a 26-year-old female kindergarten teacher with the N501Yand T478K mutant strains possibly carrying the Omicron variant.

The teacher's 28-year-old male friend who had dinner with her also tested preliminary positive for COVID-19.

The other unlinked case involves a 79-year-old man who lives in Yat Kwai House in Kwai Chung Estate. Another resident of the same building but living in a different unit and floor also tested preliminary positive for COVID-19. He is a 53-year-old man who works at the Cathay Pacific Cargo Terminal at Hong Kong International Airport and is mainly responsible for handling goods with a forklift truck.

The centre is following-up on whether the two cases are epidemiologically related.

At a press briefing this afternoon, the centre's Communicable Disease Branch Head Dr Chuang Shuk-kwan said there are more than 10 preliminary positive cases and that most of them are locally infected.

One of them is a 17-year-old student who lives in Tower 3, Grand Central in Kwun Tong. His source of infection remains unknown.

He studies at St. Joseph's Anglo-Chinese School in Kwun Tong and last went to school on January 14. His sample carries the L452R mutant strain and he was not vaccinated against COVID-19.

Additionally, a 58-year-old teacher at Delia Memorial School (Broadway) in Mei Foo also preliminarily tested positive for the virus. The patient was an invigilator for an examination attended by an earlier infected case on January 10, 11 and 14.

Meanwhile, a schoolmate of an infected case from the same school also tested preliminary positive, along with two family members.

Dr Chuang noted that it was too early to say whether there was super spreading event at that school, but conceded that a transmission event in two classes did exist.

“We need to be certain how many teachers and students are affected before we can conclude whether there is a super spreading event. But there is at least some transmission occurring.

“We are indeed very worried about the increasing number of unknown cases in the community involving the Delta variant in some cases and the Omicron variant in other cases. And there are signs that more cases are still emerging from the community testing centres.”

She called on the public to stay vigilant, avoid participating in social activities and get tested if they live near the positive cases.

“For residents or those who worked near Sham Shui Po, Un Chau Street or those who stayed near Mei Foo, please go get tested as soon as possible.”

There are eight service points in Sham Shui Po where people can undergo testing on a voluntary basis.

The Government made a restriction-testing declaration this evening covering Yat Kwai House, Tower 3, Grand Central and Fu Yuet House, Fu Cheong Estate in Sham Shui Po where confirmed and preliminary positive cases live.

Moreover, in view of one local case, two import-related cases and 10 preliminarily positive cases, 39 specified premises are included in a compulsory testing notice.

The Government will set up or reopen mobile specimen collection stations at various locations to provide free testing services.

For information and health advice on COVID-19, visit the Government's dedicated webpage.