The cleaner also infected her partner, who was not involved with the hotel, but because of their relationship, that did not surprise health authorities.
But the tipping point came after genomic testing confirmed a man and woman who arrived in Brisbane from Lebanon also picked up the B.1.1.7 strain.
They were also staying on the seventh floor of the hotel, which Chief Health Officer Jeannette Young said sounded alarm bells.
“We’re going to be very, very careful about floor seven and see whether that’s where it spread and the rest of the hotel is fine, but we don’t know, so we’re taking a really cautious approach, as we always do here in Queensland,” Dr Young said.
As a result, the hotel’s guests and staff have all been evacuated, with those in quarantine moved to the nearby Westin Hotel, where their 14-day quarantine clocks have been reset to zero.
Those who stayed at the Hotel Grand Chancellor on or after December 30 but were released are also being contacted to undergo another 14 days in quarantine, although they may be allowed to do so at home if their accommodation is deemed appropriate by health authorities.
Queensland police, who were already conducting a review of the hotel’s quarantine procedures in the wake of the cleaner’s infection, previously said they were combing through four days’ worth of CCTV footage.
But in another stroke of bad luck, Deputy Commissioner Steve Gollschewski said the seventh floor is not covered by cameras.
“Not all hotels, including this one, have CCTV everywhere and, in fact, we don’t have CCTV on that particular floor,” he said.
“So that means we have to be even more meticulous in going about our investigation, and that will be ongoing.”
Dr Young insists hotel cleaners have had PPE requirements from the start of the program, adding they have been “consistent” throughout the pandemic.
“This is new information. To have six people linked to someone who has been in quarantine, that’s different to what we’ve seen before,” she said.
“This has happened very quickly and we’re struggling to find how it’s got out of that room.”
University of Queensland epidemiologist Linda Selvey said there was a precedent for a coronavirus to spread in a hotel without the guests coming into direct contact.
“You think back to SARS and, acknowledging that was a different situation, there was an outbreak in a hotel in Hong Kong where a number of people on one floor got infected even though they didn’t have any contact with the index case,” Associate Professor Selvey said.
Authorities will now look for all potential avenues of transmission, from airconditioning, to food, and even flushing toilets, although Professor Selvey considers that last theory a “remote possibility”.
“The genomic sequencing would be enough of a warning, even if they were on different floors, although if they were on different floors, you might think it was more personnel related,” she said.
“It still could be personnel related, hopefully not, but it’s possible. You’d hope that it’s not the case that there are other people that are incubating the infection as well.”
Professor Selvey said, given the genomic testing indicates the transmission almost certainly occurred on the seventh floor, best practice was to move everyone to a different hotel.
“They don’t yet understand what happened, and we may never understand, but in the meantime, you certainly don’t want to keep people in that situation where they might be at risk of acquiring the infection,” she said.
Stuart Layt covers health, science and technology for the Brisbane Times. He was formerly the Queensland political reporter for AAP.