Hongkongers are no less weary of living under Covid-19 restrictions than people elsewhere. The lifting of most coronavirus rules by England on Monday is bound to have many feeling envious. But as the Delta variant and other mutations of the virus drive fresh waves of infection around the world, scepticism is warranted. For all the desire to travel and resume lives as before, there is still every need to be cautious. England’s relaxation means an end to most social-distancing rules and mandatory mask-wearing. Authorities are betting on relatively high levels of vaccination to ensure a safe reopening. But although about 54 per cent of people have been immunised and are therefore less likely to get seriously ill should they be infected, 14 million still have not got a jab. It is the reason the nation’s infection rates are now the worst in Europe with 50,000 a day and the numbers of deaths relentlessly climbing. Hong Kong still lists Britain among extremely high-risk areas for Covid-19, meaning people from such places are barred from entry. But there have been suggestions that the rules be changed so residents can return and much-needed workers, such as domestic helpers from Indonesia and the Philippines, can take up jobs, as long as they are vaccinated. Moves have also been afoot for stranded students who have not received jabs to be allowed back from Britain on compassionate grounds so that they can spend their summer holidays with families. The first group tours to Europe since February last year also left at the weekend, those travelling being fully immunised and having taken antibody tests, although they will have to quarantine in designated hotels on return. Such moves are obviously welcome to affected people. But it has to be remembered that vaccination rates in Hong Kong remain low, with less than 30 per cent of the population considered fully vaccinated. Officials estimate that if the present level of 30,000 jabs a day continues unabated, 70 per cent can be immunised by the end of September. But that is still the lower end of what is necessary for herd immunity, the point at which some experts contend border controls can be fully relaxed to enable quarantine-free travel. There are those who believe that 85 per cent is safer still. First Hong Kong tour group to Europe in 16 months sets off, but is it a wise move? But slow vaccination has its drawbacks, which is why there are concerns among some government advisers about allowing travel by people from high-risk areas. Those not vaccinated are at risk of infection, and those who have received jabs may not be protected against variants. England’s approach is also worrisome, ending restrictions being seen by some as providing fertile ground for the emergence of coronavirus mutations. Hong Kong has done a good job in staving off Covid-19, but the effort can too easily be undone if haste is put ahead of caution.