The city of Shanghai has discovered a COVID-19 case involving a new subvariant Omicron BA.5.2.1, an official told a briefing on Sunday, signalling the complications China faces to keep up with new mutations as it pursues its “zero-COVID” policy.

The case, found in the financial district of Pudong on July 8, was linked with a case from overseas, said Zhao Dandan, vice-director of the city’s health commission.