(To watch the full press briefing with sign language interpretation, click here.)

The Centre for Health Protection today said it is investigating 21 additional COVID-19 cases, of which 17 are locally transmitted.

Among the local cases, seven have unknown sources of infection.

At a press briefing this afternoon, the centre's Communicable Disease Branch Head Dr Chuang Shuk-kwan reported that one more case was detected on 14/F of Oi Wo House in Tai Wo Estate.

"Concerning Oi Wo House in Tai Wo Estate, I think it is similar to quite a number of other housing estates with a bit of horizontal spread of the virus that may be due to some environmental contamination when the patients of the cases, during the infectious period, stayed on the building floor.

"This might happen in the corridor or the hall or the waiting area or other places such as the place where you throw the rubbish, etc. So we do not know what exactly happened.

"But this phenomenon did happen a few times in the past, so that is why we have to move all the other residents and observe them."

She added that a close contact of the newly confirmed case, who does not live in Oi Wo House, also contracted the virus.

Dr Chuang also said the 14 environmental samples taken from Wai Lee Building in Quarry Bay tested negative for COVID-19.

The imported cases involve two patients from the Philippines and one each from Albania and India.

For information and health advice on COVID-19, visit the Government's dedicated webpage.