A working group on air change or air purifiers in catering premises was briefed today on findings concerning a cluster of COVID-19 infection cases related to sub-lineages BA.4 or BA.5 under the Omicron mutant strain arising from a restaurant for the first time.

The briefing took place during a meeting held online to discuss inspection findings at the premises and the latest epidemic developments.

The cluster of infection cases emerged from customers who had dinner at a restaurant in Kwun Tong on June 24. Up to July 4, in terms of primary cases, the cumulative number of cases at the restaurant concerned involves 15 people.

The working group’s chairman, expert members and representatives from the government departments were briefed by departments on the respective inspection findings at the premises and offered views on anti-epidemic strategies.

According to data from on-site measurement, the air change per hour or fresh air of the restaurant's seating areas reaches 7.28. However, some of its equipment, such as the exhaust fans in the kitchen and toilets, have malfunctioned. As a result, the possibility of various factors contributing to the infection cases could not be ruled out.

Noting that sub-lineages BA.4 or BA.5 are more transmissible and the possibility of large-scale infections happened overseas cannot be ruled out, the working group stressed that staff and customers of catering premises must not lower their guard.

It further explained that all catering premises operators must ensure that their fresh air related ventilation system must be properly switched on, operated, repaired and maintained on an ongoing basis while the premises are opened for business.