The first untraceable Covid-19 variant case in the community has sounded alarm bells. It appears to have confirmed growing fears that more infectious strains are spreading through undetected transmission chains in a city that is easing curbs on social-distancing restrictions. The community must be put on full alert and work with the authorities in thwarting another potentially devastating wave of the disease. The severity of the matter is reflected in the immediate quarantine of all those living in a 52-storey tower block on outlying Lantau Island, along with compulsory tests for those at no fewer than five venues visited by an infected domestic helper, the biggest operation of its kind since the pandemic began. ‘Grim situation’ as Hong Kong records first local untraceable Covid-19 mutant case Domestic helpers who are not fully vaccinated are required to undergo tests by May 9. Having a vaccination will also become a condition for their contracts and work visas in future. Officials believe the nature of helpers’ work makes them more vulnerable, but questions have been raised as to whether the measures are discriminatory. With three variant cases of a known origin already identified, the latest case involving a Filipino with no recent travel history has made the outlook even more worrying. She was carrying the N501Y and E484K mutations and had met other helpers during the incubation period. Her employers both tested negative, but the couple’s 10-month old daughter was infected. Concern has been further heightened by the discovery of at least 10 previously imported infections involving a variant suspected to be behind the current surge in India. Seven of them arrived on a flight from New Delhi on April 4. Even though there is no evidence yet of the strain having made its way into the community, such a possibility cannot be ruled out. Mutated variant from India found in 10 Hong Kong Covid-19 cases The city’s first two variant cases found in the community came after an Indian man from Dubai finished his 21 days of quarantine in a hotel and infected his friend. They were both asymptomatic and tested positive. The third case involved a domestic helper from overseas, who may have been infected before arriving in Hong Kong or during quarantine at a local hotel. The authorities must go further to review current procedures, because the recurrence of infections with variants points to weaknesses in the city’s defence system. From flight bans and quarantine for arrivals to testing and contact tracing, there is a need to look again. The decision to step up compulsory testing is the correct response, as is the appeal for more people to get vaccinated. The inroads made by variants and the easing of restrictions on dining and entertainment have made vigilance all the more important. The city must stay united to win the battle.