The Centre for Health Protection (CHP) today said that three clusters of imported COVID-19 cases involving Emirates flight EK384 arriving in Hong Kong on November 21 are likely to be epidemiologically linked.

The flight arrived from Dubai, the United Arab Emirates, via Bangkok, Thailand, with three clusters of COVID-19 cases comprising 11 patients detected.

The whole genome sequencing analysis conducted by the Department of Health's Public Health Laboratory Services Branch confirmed that some of the cases have identical genetic sequences, suggesting that the clusters are likely to be epidemiologically linked.

Among the 11 cases, eight patients (cases number 12411, 12412, 12413, 12437, 12438, 12439, 12443 and 12447) belong to a family which began their journey in Pakistan. Three of them tested positive upon arrival at Hong Kong International Airport and the other five were confirmed infected with the virus at the Penny's Bay Quarantine Centre.

Another case (case number 12420) involves a patient who boarded the flight in Bangkok and tested positive during quarantine at a designated quarantine hotel.

The remaining two cases are a couple arriving from India via Dubai (cases number 12429 and 12434). They tested positive at a designated quarantine hotel and the Penny's Bay Quarantine Centre.

The genetic sequencing analysis revealed that the 11 patients carried the L452R mutant strain, while the whole genome sequencing analysis also confirmed that it belonged to the Delta variant and that cases number 12413, 12420, 12429, 12434, 12437 and 12438 have identical genetic sequences, suggesting that these six patients are likely to be epidemiologically linked.

The CHP cannot rule out the possibility that the family cluster of eight cases may have spread the virus to other three patients by personal contact and shared use of toilets on the aircraft.

It added that there has not been a virus spread in the community as these 11 linked cases were all detected at the airport, the designated quarantine hotels and the Penny's Bay Quarantine Centre.

There were a total of 74 passengers on the flight concerned, including the above 11 cases and a case unrelated to the clusters (case number 12423).

As a number of passengers were confirmed to have COVID-19 by arrival testing, the department prohibited the landing of Emirates passenger flights from Dubai and Bangkok from November 23 to December 6.

Taking into account the latest epidemiological information, the CHP considered that the passengers of that flight may be prone to higher infection risk and thus it will adopt more prudent quarantine and testing arrangements.

Among the arrivals from that flight, four had already been sent to the Penny's Bay Quarantine Centre for quarantine after being classified as close contacts of the above confirmed cases.

For other passengers, they had to undergo a 21-day compulsory quarantine at a designated quarantine hotel as United Arab Emirates and Thailand are both listed as high-risk places.

Up till now, 57 passengers are still under quarantine at designated quarantine hotels. They tested negative by three virus tests already conducted as of yesterday.

The CHP will increase the number of tests for these people during the rest of their quarantine period. Parallel testing will also be arranged on the 19th day to further verify their negative test results before they complete their quarantine.

Meanwhile, one of the passengers of the flight concerned is a locally based aircrew member. With the exemption from compulsory quarantine, he stayed in a designated quarantine hotel upon arrival in Hong Kong and completed self-isolation on November 27. The CHP has sent him to the Penny's Bay Quarantine Centre for quarantine until December 12.

Regarding the non-local aircrews of that flight, they did not enter Hong Kong and had left the city already.

The CHP has informed the Airport Authority and the airline to monitor the health conditions of overseas aircrew and disinfect the plane thoroughly. It will also ensure the relevant designated quarantine hotel’s compliance to the infection control requirements.