Hong Kong has lifted an unprecedented lockdown for mandatory Covid-19 testing in one of its most crowded and rundown areas amid questions about its effectiveness, even as the city faces the spectre of an escalating new outbreak in a prominent middle-class neighbourhood. Health experts on Monday were left debating the justification for locking down part of Yau Tsim Mong district to test more than 7,000 residents over a two-day period, which uncovered only 13 coronavirus infections. But those who supported the drastic move noted the possibility that a security guard from the stricken district could have spread the disease to the Laguna City private housing estate in Lam Tin, where dozens of residents were evacuated from an affected block. Authorities confirmed 73 new infections citywide, amid growing speculation that the Yau Ma Tei wholesale fruit market might be next in line for a lockdown, which would have a major impact on vendors ahead of their critical selling period for the Lunar New Year holiday. Also on Monday, Secretary for Food and Health Professor Sophia Chan Siu-chee approved the Pfizer-BioNTech vaccine for the first roll-out in Hong Kong, which was expected to start after the festive season break. In a different environment from the mostly dilapidated tenement buildings with subdivided flats in the area locked down over the weekend, health authorities turned their focus to Block 5 of Laguna City, where they ordered the evacuation of dozens of residents living in flats marked “E”. Residents showing symptoms of Covid-19 were admitted to hospital and the rest sent to quarantine camps after experts said the coronavirus might be spreading vertically through pipes or lightwells in a “chimney effect”. At least 10 infections have emerged in the building over the past two weeks. Following an inspection of the site, Professor Yuen Kwok-yung, who advises the government on the health crisis, said the infected security guard who lived on Reclamation Street in Yau Tsim Mong might have brought the virus to the estate. “That’s why one could understand the [lockdown] in the Yau Tsim Mong district was necessary,” he said. “If we cannot control the spread of the virus there, [it] could be spread to many other places across Hong Kong.” ‘Chimney effect’ may be behind Covid-19 outbreak at Laguna City For 44 hours beginning early Saturday, thousands of residents in the restricted zone in Jordan were prevented from leaving as mandatory testing was carried out. More than 3,000 government workers from 16 departments were involved in the operation, including about 50 staff members who spoke Nepali, Urdu and Hindi and helped members of ethnic minority groups navigate the process. While the government is unsure exactly how many people live in the restricted area, putting the number at about 8,000, officials were prepared to test roughly 10,000 residents. No one answered the door at about 470 flats, according to home affairs minister Caspar Tsui Ying-wai. Chan has defended the screening as necessary, noting the 13 cases translated into a 0.17 per cent positive rate, which was broadly in line with similar community testing efforts. But respiratory medicine specialist Dr Leung Chi-chiu said the lockdown was not cost-effective. “The direct and indirect costs are relatively high, with 3,000 staff deployed, coupled with the impact on residents who were immobilised for two days,” he said. “But with 13 cases found in nine households, the positive rate is not that high.” Leung also questioned whether it was necessary to seal off the zone, pointing out that residents in other areas hit by outbreaks had largely been willing to undergo testing. Ben Cowling, a professor of epidemiology at the University of Hong Kong (HKU), agreed that the relatively few cases detected had cast doubt on the effectiveness of the strategy. “I’m not sure locking down other small parts of the city would make a lot of difference in getting on top of the case numbers right now,” he said. “We’ve seen this sort of approach being used very successfully in mainland China, but it’s used in a quite different way, where they’ll lock down and test everybody probably two times, not just once, with the aim of getting infections to zero very, very quickly. That’s not what’s been done in Hong Kong.” But Yuen, also from HKU, argued the lockdown was needed, noting the 0.17 per cent positive rate was higher than one resulting from voluntary mass screening carried out in September last year. About 1.78 million residents registered for testing. “If we are comparing the positive rate with the voluntary mass screening programme, with a positive rate of about 0.004 per cent, then a 0.17 per cent this time was actually fair,” he said. HKU microbiologist Dr Ho Pak-leung stressed the positive rate should not be calculated based solely on the number of new screenings. “Before the government sealed off the area, there were 150 to 160 infected cases already discovered in the zone,” he said. “If we add the 13 new cases to that, the positive rate should in fact be nearly 2.5 per cent.” Residents in the restricted zone awoke to the sight of police officers and health workers in full quarantine gear patrolling the area as sanitation crews cleaned the streets, the acrid smell of bleaching chemicals lingering in the air. Store owners, some wearing face shields in addition to masks, complained the forced closure of their business over the weekend had only made it more difficult to pay their rent. “Saturdays and Sundays are usually more packed than weekdays, with people coming to the wet market, so of course we lost money, because we didn’t open on the weekend,” said a 66-year-old vegetable market store owner, who did not want to give his full name. “But what can you do?” Policy U-turns: Carrie Lam ought to welcome more views, observers say Another vegetable store owner, who asked to remain anonymous, said the government had made the right decision. “The lockdown makes me feel safer,” she said. “It makes the residents here feel safer and hopefully we don’t need to worry about any more outbreaks here.” But just one MTR stop to the north in Yau Ma Tei, stall owners at the wholesale fruit market were wondering if they were next in line. Chinese University respiratory medicine expert Professor David Hui Shu-cheong raised the possibility on Sunday of locking down the area, where more than 60 cases have emerged. The government has refused to comment on the matter. Yeung Mun-sun, a 57-year-old fruit store owner, questioned whether the drastic step would be needed. “If the government should impose a lockdown here, there should be no double standards and they should also impose a lockdown on other wet markets as well,” he said. “The market is open-air and our hygiene standards are up to par. There are no residential buildings here, so why impose a lockdown?” Cheung Chi-cheong, vice-chairman of the Kowloon Fruit and Vegetable Merchants Association, said the government should ideally notify vendors three or four days in advance so they could make preparations. “[Vendors] have already arranged most of the arrivals of fruit [for the Lunar New Year], but the storage life for the fruits is limited, maybe two to three days,” he said. “If we knew a lockdown was coming, we might try to cut the supply.” In approving the vaccine made by Germany’s BioNTech and distributed by the mainland’s Fosun Pharma, health minister Chan said the government would continue to receive the latest clinical data and quality certification documents would be provided for each batch. The city’s coronavirus tally stood at 10,158 cases, while the number of related fatalities rose to 170 after a 94-year-old woman died at Queen Elizabeth Hospital early in the morning. More than 60 people also tested preliminary-positive.