The West Australian government knew the Mercure Hotel had issues with ventilation weeks before the outbreak that sent the state into lockdown.
A report prepared by occupational hygienist Laurie Glossop in March found three out of the 10 quarantine hotels in WA were rated “high risk” for “possible transmission of SARS-CoV-2 through an inhalation/air pathway in hotel quarantine”.
Those hotels included the Mercure Hotel, the Four Points Hotel and the Novotel Langley Hotel.
One of the recommendations to reduce the probability of infection at the high-risk locations was to move guests “at least one room further away” if they were next to or directly opposite a room containing a guest who had tested positive to Covid.
The final report was handed to WA’s Health Department on March 30, and made public on Tuesday.
According to the ABC, it took more than a fortnight for Premier Mark McGowan to be advised that the Mercure should no longer be made available to high-risk return travellers.
WA Chief Health Officer Andy Robertson said on Monday the decisions surrounding guests inside the quarantine hotels were made on a case-by-case basis.
"If we had a family for example, with a number of people within that family where there is a higher viral load, then we would obviously move people from around that family," he said.
"I saw a report on April 8 that said all of the hotels, with mitigations, could continue to be used as quarantine hotels.
"We already had people in those hotels, our hotels are full," he said.
"There isn't a spare hotel we could move people to. There is no easy solution."
Mercure Hotel outbreak spread through corridor
The Mercure Hotel became the site of an outbreak after the virus spread between rooms of returned travellers who were staying on the same floor.
Genomic testing confirmed the virus initially leaked into the corridors from a couple who had returned from India.
The man tested positive on April 13, and his wife contracted the virus two days later.
A pregnant mother and her four-year-old daughter who were staying across the hall tested positive on April 16.
A Victorian man who had been staying in a room adjacent to the Indian couple left the hotel on April 17 and spent five days in the community, unknowingly infecting at least two other people.
Victorian authorities said he was asymptomatic.
Health Officer warned Premier of risks
WA Chief Health Officer Andy Robertson wrote to the premier last Friday advising that the Mercure was the highest-risk of the three hotels and it should no longer accommodate returned travellers.
In his letter to the premier, Dr Robertson said the risks could be mitigated by changes including installing HEPA air filters in rooms with positive cases.
It was commissioned after a security guard at the Sheraton contracted COVID-19 in January, prompting a five-day lockdown.
Premier Mark McGowan said the Mercure would no longer accommodate returned travellers and the government would review the continued use of the other high-risk hotels.
A plan to transition the Mercure to a "low-risk" quarantine hotel for seasonal workers will also be reviewed.
Opposition Leader Mia Davies blamed the McGowan government's failure to address "systemic gaps" in the hotel quarantine system for the outbreak.
- with AAP
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