A likely source of the recent local Covid-19 outbreaks is people who were infected outside Hong Kong. When residents fled the outbreaks in Europe and the United States, or otherwise returned from overseas trips in previous months, they were quarantined, tested and those found positive were treated. To better understand the latest outbreaks, data is needed on all border and boundary crossings and the risk of leakage of the virus into Hong Kong. Ideally, the data should be broken down into meaningful categories, including employment and social characteristics, which makes it easier to understand and predict people’s movements once on the ground. Pilots , truck drivers, businessmen – who are quarantined, who are not? Who are tested, who are not? When I asked epidemiologists and health experts on a recent radio show, it appeared to me that they research the virus but may not have a full understanding of immigration data. The government may be unnecessarily reticent about disclosure. To sustain our city, we need essential crossings to continue. We would be without food if we did not. A good understanding by the community of cross-border and boundary movements will allow the community to take common-sense precautions based on their perception of the risks. The community responsiveness, including the immediate use of masks, has kept Hong Kong safe from the virus – well beyond what other communities have been able to achieve. Transparency of movements across our borders and boundaries will help the community guard itself against leakage and spread of the virus. Paul Zimmerman, district councillor, Pok Fu Lam; CEO, Designing Hong Kong Hong Kong should follow Wuhan on ‘batch’ testing For a few days running, Hong Kong has had more new Covid-19 cases than all of mainland China, raising the possibility of months of costly social and economic disruption to bring it under control. How about taking a leaf out of China’s playbook and repeating here what was done in Wuhan in mid-May, when the city’s entire population was tested at once across two weeks after six new local cases emerged? Using the same methods, such as combining five to 10 samples in a single batch to cut the number of tests required in the first round, and only then retesting the individual members of any batch that tests positive, should make it a realistic proposition for Hong Kong and enable the health authorities to rapidly control this outbreak. Somebody in government can run the numbers, but I am quite sure that if it is done on a batch basis, the cost of testing everyone is a lot less than the cost of the economic disruption of imposing more controls on everyone for weeks or months if the current outbreak continues. Covid-19 return means more woe for economy, finance chief warns If local testing capacity is insufficient, perhaps numbered batches of combined samples can be sent across the border to speed up the process. As long as the samples sent over are merely numbered, as opposed to identifying people directly, and each contains a mixture of combined samples from many individuals, the medical privacy implications should be easily manageable and enable Hong Kong to take advantage of the plentiful testing capacity available across the border – to get the job done quickly before things escalate further. As the unfortunate experience of many countries has shown, this virus is very unforgiving of delays in containment, so speed is of the essence. James Rodriguez de Castro, Deep Water Bay