Judging the success of Hong Kong’s recent voluntary rapid antigen self-testing effort cannot be done with great accuracy. While one aim of the three-day exercise was to reveal undetected asymptomatic cases, its discretionary nature meant the information collected was limited. Only those who tested positive were required to upload results to a government website, so determining how many took part is guesswork. Yet, the process was useful for authorities and important for the city, beyond those who were undoubtedly alerted; lessons were learned and valuable experience gained for when Covid-19 next threatens. The fifth wave of the coronavirus was already in decline when outgoing Chief Executive Carrie Lam Cheng Yuet-ngor unveiled the scheme on April 2 and announced that free packs containing 20 rapid antigen test (RAT) kits were being distributed to almost 3 million households across the city. Packing and delivering so many items was a logistical challenge, but would appear to have been accomplished with few hitches. Officials can similarly claim success in that preliminary data points to more people self-testing. Before, polymerase chain reaction (PCR) and RAT tests were roughly equal, but during the three days, PCR numbers dropped and those for RAT increased. Asymptomatic RAT figures also rose from about 35 per cent to 65, being to health authorities another telltale sign. With daily infections having dramatically fallen and closing in on three figures, compared to the peak on March 2 and 3 of between 76,000 and 77,000, the worst is behind us. Identifying as many cases as possible, particularly those that show few or no symptoms, remains important to prevent a resurgence. Mass-testing using the PCR, laboratory-based method, with mandatory lockdowns of homes, is the most effective way to screen for the disease. But Hong Kong is still logistically unprepared, so until the necessary resources are in place, voluntary RAT testing is the next best approach. Chinese University of Hong Kong team develops test for risk of long Covid With the city expected to begin relaxing social-distancing rules on April 21, authorities are also in a better position to assess circumstances. They plan to ease restrictions in three stages, starting with letting restaurants open for dine-in services beyond 6pm and allowing the reopening of places such as fitness centres, cinemas and massage parlours. A decision is also likely to factor in whether companies that have been requiring staff to work from home give the go-ahead for a return to offices. Everyone in Hong Kong now has RAT kits. They have learned to self-test and get to know the reporting system. Hundreds of people unaware they were infected have been alerted and have medication to recover and know how to isolate to protect others. The next Covid outbreak is not a matter of if, but when, and we are better prepared.