Government employees check whether residents subject to mandatory testing have an SMS notification containing a negative test result or are wearing a wristband to prove that they have been tested during a targeted testing operation in Kowloon City, Hong Kong, Feb 2, 2021. (PHOTO/HKSAR GOVERNMENT)

HONG KONG - Hong Kong reported 19 new COVID-19 infections on Saturday as the government announced to tighten its compulsory testing criteria to further curb the spread of the virus in the city.

Any residential building that records a confirmed COVID-19 case, regardless of whether it is traceable or not, will be included in the compulsory testing notice starting Saturday, an official said at a briefing.

Three new patients were linked to the cluster originated from the third runway project at the Hong Kong airport. The cluster now has 27 confirmed cases

The new requirement aims to detect silent carriers to cut the transmission chain as soon as possible, said Centre for Health Protection Controller Ronald Lam.

The 19 new infections reported on Saturday included three imported cases and 16 locally transmitted ones, six of which were untraceable. 

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One of the untraceable case was detected during compulsory testing in Yau Tsim Mong district, Lam said.

Three new patients were linked to the cluster originated from the third runway project at the Hong Kong airport. They were close contacts of construction workers at the construction site. The cluster now has 27 confirmed cases, including that of 15 workers and 12 family members.  

"There are quite a number of asymptomatic cases detected from the Hong Kong International Airport Three-runway System construction site cluster outbreak," said Lam. "Imagine these asymptomatic people going back to their homes or residential places, that could possibly constitute another undetected transmission chain."

The imported cases involved a domestic helper from the Philippines and travelers from South Africa and Pakistan.

Saturday's new additions brought the overall infection tally in the financial hub to 10,608.

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According to the Hospital Authority, there were 545 patients being treated in 24 public hospitals and the AsiaWorld-Expo community treatment facility, including 24 in critical condition.