Isolation ward malfunction triggers infection worries

A negative-pressure ward at Princess Margaret Hospital's infectious disease center malfunctioned for half an hour yesterday, the Hospital Authority said, leading to fears the virus may have spread to other wards.

Linda Yu Wai-ling, chief manager for clinical effectiveness and technology, said she did not have details on the number of people affected and whether there were Covid-19 patients.

The authority is investigating the incident and will announce details later.

"Currently, all patients have to wear a surgical mask and our health-care workers have protective gear," Yu said. "To a certain extent, this can reduce the impact."

A negative-pressure room uses lower air pressure to allow airflow into the room without any escaping. The rooms are used to isolate patients with infectious diseases to prevent contaminated air flowing into other rooms.

A minimum of 12 airflow changes each hour must be maintained to sustain the desired environment depending on the size and purpose of the room.

Arisina Ma Chung-yee, Hong Kong Public Doctors' Association president, said the impact would depend on the failure level of the system's control panel and the affected area.

"I think it could have been that the air exchange ventilation cycle failed to work properly. Virus droplets could flow out from the confirmed patient's room when the door was opened and closed," Ma said. If people were coming in and out of the isolated ward, the contaminated air might have flowed out, Ma added.

Usually, there is a signal or alarm to alert the staff when the facility is not working properly, Ma said, but it depends on the extent of system failure.

The Hospital Authority Infectious Disease Centre at Princess Margaret Hospital was the first such center in Hong Kong and was built after the 2003 SARS outbreak. It has 108 isolation beds.

Meanwhile, Hong Kong recorded five more new Covid-19 cases yesterday, taking the overall tally to 1,010.

It was the second day in a row that the city recorded single-digit new cases.

The Center for Health Protection's head of communicable diseases, Chuang Shuk-kwan, said cases had an age range of one to 79 years old, with four having a history of travel, including a 14-month-old baby girl who had been to Britain with her family.

The foreign domestic helper employed by the baby girl's family tested positive last week, while the baby's mother, grandparents and her newborn brother have shown no symptoms and are staying at the quarantine center.

The only local case was a 67-year-old man who is a close contact of a confirmed case.

Chuang said the single-digit numbers in these two days could be due to fewer arrivals in Hong Kong and could be related to general government clinics and private doctors closing for the four-day holiday, leading to fewer deep-throat test samples being collected.

Passengers coming from Britain, America and Europe are now required to wait at AsiaWorld-Expo until their virus test is out, but some travelers from a transit flight were able to leave before the results came out.

Chuang said those arrivals did not need to wait for the result but they were still given a specimen bottle for the test.

sophie.hui@singtaonewscorp.com