Vaccinating the public to achieve herd immunity against Covid-19 infections has always been the common goal. This is not only for the protection of individuals and the wider community, but also for the way of life and the economy to get back to normal. Attempts to hit this target, however, may be distracted by questions over the threshold for immunisation and vaccine efficacies as fast-spreading variants deepen the global health crisis. But the principle remains unchanged. It is imperative to get as many people vaccinated as possible so curbs can be eased in a way that will not endanger public health. For the first time, officials have acknowledged that the 70 per cent rate of vaccination would be an attainable goal by late September. This makes further relaxation of health restrictions and reopening of borders with the mainland and Macau closer to reality. Medical experts, however, have argued that herd immunity may no longer be a realistic goal, referring to a lower level of protection against the more infectious variants. There has also been suggestion that the public needs to achieve a vaccination rate of more than 90 per cent for social-distancing measures to be further relaxed. The different narratives by the government and medical experts over the way forward can be confusing for the public. This is not helped by the apparent lack of progress over the much-touted border reopening, despite the encouraging signs of rising vaccination figures – and weeks of no local infections with unknown origins. The notion of learning to live with the virus, as suggested by some scientists and practised in Britain and some foreign countries, may somehow dampen the incentive for people to come forward for their jabs. The government has been juggling between the goals of zero infections – a key condition for border reopening – and the gradual resumption of public and economic activities. This has to be done with extreme caution, taking into account the prevailing local and overseas epidemic situation. Be it a 70 or 90 per cent inoculation rate for herd community – the current level of some 2.24 million people having taken two shots, or 30 per cent of the 7.5 million population – is still a long way off. The city must continue to boost the rate as it contemplates relaxation of health rules with caution.