One of them is a local air crew member who tested positive for the N501Y mutant strain.
He received his third dose of the BioNTech vaccine in November.
The 46-year-old gave negative Covid test results on December 19 and 20 before flying to the US on December 22.
But samples collected upon his return on December 25 were positive for the coronavirus.
The man lives in The Visionary in Tung Chung.
Health authorities have issued compulsory testing orders for the block he lives in and the places he visited during his incubation period.
The remaining patients, two men and six women, were aged between between 19 and 57.
They had flown in from Pakistan, the US, Nigeria, Ethiopia, France, South Africa and Germany.