Hong Kong should only resume tracing the source of infection of every Covid-19 patient when daily caseloads fall to low double digits, a government pandemic adviser has said, while another expert expects it to be a prerequisite for the city to resume quarantine-free travel with mainland China. During previous coronavirus outbreaks, local authorities carried out extensive contact tracing to curb transmission chains and quarantine any potential patients. However, such measures were halted as the fifth wave peaked, with tens of thousands of infections recorded on a daily basis. As daily infections had fallen to about 400 in the past week, government health expert Professor David Hui Shu-cheong of Chinese University said it was still not the right time to implement contact tracing as cases were still in the three-digit range. “When there had been a rather extensive outbreak in the community, even though we are doing contact tracing now it would not help in achieving zero cases,” he said. Health officials reported 366 Covid-19 infections on Friday, including 14 imported cases, and 11 additional deaths. The city’s overall coronavirus tally since the pandemic began stood at 1,203,847, with 9,298 related fatalities. The government also announced it would lift the red outbound travel alert for all foreign countries in May, citing a general “downward trend” in global cases. The measure was initially implemented on March 17, 2020, during the early stages of the Covid-19 pandemic. Meanwhile, Hui said contact tracing could be resumed when daily cases fell to between 20 and 30, as part of a zero-infection policy to restore quarantine-free travel with the mainland. But he added that it would also depend on whether the central government opted to change the criteria for reopening the border. Dr Chuang Shuk-kwan, head of the communicable disease branch at the Centre for Health Protection, said the decision to use extensive contact tracing was not based on a set threshold for daily coronavirus cases. In late February, officials announced that the “Leave Home Safe” app, which also helped trace possible patients by issuing notifications to residents who had visited premises that reported confirmed Covid-19 cases, would be temporarily halted. 5 charged with trespassing for not using ‘Leave Home Safe’ app During the same period, a fifth contact-tracing office, managed by staff from the Independent Commission Against Corruption, was established to cut off coronavirus transmission chains. Despite the pause in contact tracing during the peak of the fifth wave, health authorities said they were still conducting such measures in high-risk places, such as schools and care homes. But respiratory medicine expert Dr Leung Chi-chiu said all Covid-positive cases should be required to upload their location information from the “Leave Home Safe” app to the government’s database. “Authorities could then quickly identify any clusters of infections in certain places with the help of technology,” he said. “If transmissions in those places are not followed up, they could lead to a rebound in infections.” Leung said he believed that contact tracing would be a prerequisite for the resumption of quarantine-free travel with the mainland, noting he expected the central government would tighten anti-epidemic measures following the recent outbreaks there. University of Hong Kong clinical virologist Dr Siddharth Sridhar, however, said it was no longer necessary for health authorities to trace every single case in the community. “Right now, cases are going down spontaneously. And once the sixth wave starts off, you’re going to see a rapid rise in cases [just like the fifth wave], so manpower is quickly going to be overwhelmed,” he said. “Of course, Covid-19 outbreaks in epidemiologically sensitive settings such as schools, residential care homes for the elderly and hospitals should continue to be investigated.” Sridhar added that authorities should focus on vaccinating the elderly and high-risk groups and improving the delivery of Covid-19 antivirals in community settings. “We have to progress from trying to curtail transmission completely [eventually an impossible task] to protecting our most vulnerable groups using targeted pharmacological interventions,” he said. Mainland Chinese worker at Covid holding centre found dead in Hong Kong hotel Hong Kong currently uses two oral Covid-19 drugs, MSD’s molnupiravir and Pfizer’s Paxlovid, to treat high-risk patients. Under the extensive contact-tracing mechanism, a team of officers from Hong Kong’s disciplined services swing into action each time someone tests positive or has a preliminary-positive result. First, they try to find out as much as possible about where the patient has been, and with whom, over the past 14 days. Then they try to find all those contacts and notify them that they might have to be quarantined and tested for Covid-19.