Hong Kong is reviving one of its toughest "COVID zero" measures, forcing patients with even mild infections caused by new omicron subvariants and their close contacts into centralized quarantine to tame any spread.

People infected with substrains including BA.2.12.1 who aren’t severely sick, as well as their close contacts, will be sent to government facilities like Penny’s Bay as officials try to ring-fence their spread. The rule has been enforced for all 34 people with the newest forms of the virus in the city thus far, officials said, including at least two families linked to a cluster at a Canadian school who argued that their living situations were suitable for home isolation.

Both families said they had requested to quarantine at home because they have their own kitchen and bathrooms — a standard requirement for approval — but health authorities told them they would be sent to an isolation facility because the cluster involved a new subvariant, according to the families.