People wearing face masks amid concerns of the COVID-19 coronavirus walk past a Christmas display at a shopping mall in the Wan Chai district of Hong Kong on Dec 24, 2020.
(ISAAC LAWRENCE / AFP)

HONG KONG – Hong Kong banned the use of a mask with any exhalation valve or vent for people under compulsory hotel quarantine and advised the public against wearing them.

During an investigation into two COVID-19 confirmed cases, the government suspected a person may have transmitted the virus to another while wearing such a mask when his hotel room door was open.

The government strongly advised the public against wearing masks with exhalation valve or vent as they cannot effectively filter droplets in exhaled air

The two cases involved two men, aged 62 and 36 respectively, who had returned from overseas and staying at Regal Airport Hotel located in Chek Lap Kok for compulsory quarantine. They checked-in to rooms opposite to each other on the 5th floor.

To avoid a similar situation from recurring, the government has updated the directions under the Prevention and Control of Disease (Requirements and Directions) (Business and Premises) Regulation, according to a statement issued late Wednesday.

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The government also strongly advised the public against wearing such masks as these masks cannot effectively filter droplets in exhaled air. 

"The risk posed to surrounding people will be increased if the wearer is infected with novel coronavirus or other respiratory viruses," the statement reads.

It recommended that anyone undergoing quarataine at designated hotels should wear surgical masks properly during check-in or when the hotel room door is opened to effectively prevent the COVID-19 transmission.

"Hotel staff and air crew should remind guests and passengers respectively not to use masks with any exhalation valve or vent," the government added.

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The breathable mask, also dupped "selfish mask," were largely worn in pre-pandemic times by construction workers.

In August last year, the US Centers for Disease Control and Prevention also warned the public against wearing such masks as a protection against COVID-19, saying "the hole in the material may allow your respiratory droplets to escape and reach others."