The experts involved in the K11 MUSEA investigation have considered all available evidence and exercised their duty and judgement based on scientific evidence and professional knowledge, the Government said today.
It made the statement in response to recent comments on the air change requirement for catering businesses and the findings of a related site investigation at a restaurant in K11 MUSEA in early March.
It pointed out that available information does not indicate any flaws in the investigation process.
The Centre for Health Protection invited Prof Yuen Kwok-yung to join a multidisciplinary team to conduct a visit to the restaurant in the mall on March 1 to investigate the cause of the cluster of COVID-19 cases.
The team consisted of an epidemiologist from the centre, the Food & Environmental Hygiene Department, the Electrical & Mechanical Services Department (EMSD) and the Environmental Protection Department.
This was necessary as engineers and epidemiologists do not have expertise in virology and infectious diseases.
Airflow measurements taken by the Government during the investigation were about the total outdoor air at the main supply air duct to the seating areas and double-checking the airflow in the supply air duct connection to each of the fan coil units where accessible. These sought to simulate the dine-in situations involving the occurrence of this cluster.
Following the on-site investigation with airflow measurements by engineers, a meeting was chaired by Prof Yuen. Members of the team listened to all the initial findings reported by different team members and came up with a consensus of the initial findings and the corresponding recommendations.
The conclusion was that the outbreak was more likely due to the low air change per hour of 1.2 and 2.1 for certain parts of the dining area of the lower floor on which the outbreak occurred, rather than due to transmission by contact at the adjacent tea room where environmental samples were found to be positive with the virus.
The statement noted that there was a comment that air ventilation of the seating area and the kitchen should be taken together for food premises. It said that this is not true.
The law requires separate ventilation systems for the seating area and the kitchen, and the guide for application for restaurant licences has also made this point clear.
The actual ventilation system for the restaurant's kitchen is in fact connected to the central system of K11 MUSEA and is completely independent of that for its seating area.
The Government also clarified that no departments, including the EMSD, have been commissioned to conduct any study referred to by the restaurant on March 31.
While Prof Yuen suggested the need for at least six air changes per hour in eateries or putting in place air purifiers meeting certain specifications as an alternative, the Government had conducted a literature review in August and September last year and took a view on adopting this threshold as the basis for the voluntary declaration system launched on October 16 last year, which is now codified into the mandatory registration system.
The statement stressed that the requirements of air change per hour in eateries or air purifiers as an alternative are based on scientific evidence available, overseas guidelines and consensus of experts in relevant disciplines.
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