One in four Covid-19 patients in Hong Kong travelled to places outside the pandemic’s new epicentres in Europe and North America, a Post analysis has found. The findings have sparked calls for mandatory testing on all inbound travellers at border facilities instead of just those from countries with the most serious outbreaks. With the city’s new coronavirus infection figures dwindling to just one on Thursday, the lowest in more than five weeks, attention has turned to long-term containment strategy, as officials mull plans to reopen the economy and society after weeks of lockdown and social-distancing restrictions. The city has barred all non-residents from entry from overseas countries since March 25, and required all returning residents as well as visitors from mainland China, Macau and Taiwan to undergo quarantine for 14 days. Health authorities began collecting deep throat saliva samples from groups deemed to have higher health risks arriving at the airport on March 19, and later expanded the scheme to cover all arrivals. However, only those coming back from Europe and the United States have been held at AsiaWorld-Expo’s testing centre until their test results returned negative. From Sunday, such arrangements would be extended to all airport arrivals. People entering the city through the three land checkpoints that remain open are not tested, except those with a travel history to Hubei province in the past two weeks. They are allowed to go home first and return a deep throat saliva sample in a specimen bottle later. Experts now believe that on-site testing at the air and land border should widen to include all inbound travellers, and the scheme should form a key plank in the city’s long-term battle plan against the coronavirus and a potential resurgence of imported infections. A Post analysis of all 1,021 cases in the city to date showed 611, or 60 per cent, were imported or close contacts of imported cases. But some not officially classified as imported infections had also travelled, with a total of 950 trips outside Hong Kong made by all patients. Among all the city’s cases, 25 per cent had been to Asia (162 cases), South America (43), Africa (23) or Australia/New Zealand (nine). Europe (595 cases) and North America (162) claimed the lion’s share of the travel history. Britain and the United States topped the breakdown, with 393 and 84 Covid-19 patients, respectively, having made a recent visit to those places, many of them students. But far-flung places like Peru (15 cases) and Egypt (12) also featured prominently in the findings after local tour groups and holidaymakers journeyed to those countries, leading to cluster outbreaks upon their return. Infectious disease specialist Dr Joseph Tsang Kay-yan called the set of figures “alarming”, and said the authorities should extend compulsory on-site testing to all travellers. Citing recent reports of travellers skirting the testing rule by returning via Doha or other transit spots outside Europe and North America, Tsang said “some infected persons might have already slipped through the net and are spreading the disease in our community”. He added that testing of all arrivals should have been carried out earlier, as official figures showed six asymptomatic patients had tested positive for the virus even after their 14-day home quarantine had ended. They were not found earlier because they were not given specimen bottles at the airport upon arrival in March, and only discovered they were infected after being checked by private doctors following home quarantine. Tsang believes the case for mandatory testing at the border has grown stronger as the city prepares to resume economic and social activities. “The defence line will be pushed to the border long after local transmissions have stopped, because this is a global pandemic,” he said. The defence line will be pushed to the border long after local transmissions have stopped, because this is a global pandemic Infectious disease specialist Dr Joseph Tsang Dr Leung Chi-chiu, chairman of the Hong Kong Medical Association Advisory Committee on Communicable Diseases, agreed, saying the government should consider placing travellers awaiting test results at hotels and quarantine facilities near the airport. At present, the AsiaWorld-Expo testing centre can handle 400 tests at any given time, and the city’s quarantine centres can accommodate some 1,700 people. Chinese University respiratory medicine expert Professor David Hui Shu-cheong said the city’s long-term testing plan should pay close attention to infection rates in the southern hemisphere, as places like Australia would enter the winter season soon, raising fears of a spike in cases as scientists believe cooler temperatures might help the contagion spread more quickly. “But if a country has not reported a new case in 28 days, or two incubation periods, then Hong Kong can consider suspending the testing of those arrivals to free up testing capacity for others,” Hui said. In response, Dr Chuang Shuk-kwan, head of the communicable disease branch of the Centre for Health Protection said on Saturday that the authorities were listening to experts’ advice and “actively exploring the options” to conduct virus tests for all inbound travellers at land and air borders.