Hong Kong’s first community infection of a mutant Covid-19 strain involved the South African variant, officials revealed on Tuesday, with transmission likely to have taken place at a quarantine hotel via door hooks used by staff to deliver meal boxes to guests.
Local health authorities also confirmed eight new coronavirus cases on Tuesday, including two people who recently arrived from mainland China.
One of them, a woman who was isolating at home in a subdivided flat shared with as many as 20 people, tested positive despite previously having received two Covid-19 jabs on the mainland.
Do you have questions about the biggest topics and trends from around the world? Get the answers with SCMP Knowledge, our new platform of curated content with explainers, FAQs, analyses and infographics brought to you by our award-winning team.
The other patient entered the city under a quarantine-free scheme allowing Hongkongers in Guangdong province and Macau with a negative test result to return, potentially raising questions about the government’s plan to expand the programme to cover the whole of the country.
Of Tuesday’s three imported cases, two were recent arrivals from India, including a patient who travelled on an April 4 flight where 53 passengers so far have been confirmed as infected.
The third infection, from the Philippines, involved a woman who was also found to be carrying the N501Y mutation, taking the total number of imported cases detected with that strain to 230, including 99 that resembled the one first found in Britain, and 34 for the South African variant.
Hong Kong has hit both countries, along with Pakistan, with a two-week flight ban which started on Tuesday, after five imported cases of mutant strains were found over a seven-day period from all three.
Officials also revealed the findings of a much-anticipated probe into the origins of the first mutant infection detected in the community, involving a 29-year-old engineer who arrived from Dubai in March and was confirmed infected on Saturday.
It concluded he was likely to have acquired the virus while quarantining in Tsim Sha Tsui at the Ramada Hong Kong Grand Hotel, where two other guests on the same floor also carried the South African variant.
“They all carry the N501Y and E484K mutations, with their genome sequences highly similar … we cannot rule out the high possibility that the patient got infected in the hotel,” said Dr Chuang Shuk-kwan, head of the Centre for Health Protection’s communicable disease branch.
One of the two guests stayed in an adjacent room to the 29-year-old while the other one was along the hall. Eight to 10 other guests found to be infected from other floors of the hotel only carried the N501Y mutation.
As experts found no problems with the hotel’s ventilation and drainage systems, the focus turned to S-shaped door hooks used by employees to hang meal boxes for self-isolating guests, who would later put them back there.
Chuang said the virus could have been exchanged through contact with the hooks, which were “hard to clean”.
All designated quarantine hotels which had been using the hooks were ordered to put the meals on chairs instead, Chuang said. Some premises had used the hooks because they did not have much space for chairs in narrow corridors, she added.
Among the latest confirmed cases was a 29-year-old Indonesian domestic worker who had also recently stayed at the Ramada hotel although on a different floor from the 29-year-old engineer.
One of the two women who arrived from the mainland and were found to be infected was a 56-year-old who came in from Fujian province.
She stayed in a Tsuen Wan subdivided flat and was under home quarantine when confirmed. She did not leave home, though the people living with her had done so.
The other was a 46-year-old who came in from Dongguan and worked as a housekeeper at the Nina Hotel in Tsuen Wan West. The roughly 40 guests who stayed in the 10 rooms she cleaned were quarantined, together with more than 10 colleagues.
The tourism board, which has worked with about 140 hotels on the “Staycation Delights” programme to boost occupancy rates, later said those who had booked a stay at the Tsuen Wan West property would be allowed to postpone or cancel for free.
Government coronavirus adviser Professor David Hui Shu-cheong, an infectious disease expert at Chinese University, said virus particles could stay on metal surfaces such as door hooks for two to three days.
Dr Leung Chi-chiu, a respiratory medicine specialist, however, said he had reservations about the door-hook theory.
“It’s unlikely the guests would have touched the hook with a handful of sneeze and saliva. I think it’s more likely the patients exhaled virus particles into narrow corridors when opening the door to get their meals, which had then stayed there for a long time.”
He said premises with narrow corridors and poor ventilation should not be chosen as quarantine hotels, or they should install systems that ensured the air was changed six times per hour.
On the two infected travellers from the mainland, Leung said the government should only expand the “Return2HK” scheme to cover major cities where testing rates were high, to avoid importing potential carriers into Hong Kong.
Mutant strains in general could be 60 to 70 per cent more infectious than the non-variant form of the coronavirus, Hui told a radio programme earlier in the day.
Meanwhile, sources said that a long-awaited Covid-19 travel bubble between Hong Kong and Singapore would remain on course for a mid-May launch.
Hong Kong has recorded 11,703 confirmed Covid-19 infections, with 209 related deaths.
As of Tuesday, 758,679 people had received their first dose of a vaccine, amounting to 10.1 per cent of the city’s 7.5 million population. A total of 390,976 people, or 5.2 per cent of the population, had received their second dose.
More from South China Morning Post:
This article Coronavirus: South African variant confirmed as Hong Kong’s first local case of mutated strain, transmission linked to hotel door hooks used for meal deliveries first appeared on South China Morning Post