Epidemiologist Nick Wilson is branding the Government's shutdown of two managed isolation facilities as a slow response to a Covid-19 transmission risk known months ago.
Both the Grand Millennium and Grand Mercure managed isolation facilities in Auckland have been closed to further returnees following investigations into virus transmission through ventilation systems.
MIQ head Brigadier Jim Bliss confirmed the recommendation, made by a joint Ministry of Health and MIQ technical advisory group.
The change took effect from Wednesday last week, as reviews into ventilation as a potential transmission source were underway. The change would persist until the reviews concluded, expected at the end of the month.
The group also recommended that all returnees currently at the Grand Mercure be tested at day seven of their stay, in addition to other testing. People in managed isolation are currently tested within 24 hours of arrival, on day three and day 12.
Bliss said recent instances involving new variants had shown aerosol transmission played a "greater role" in how Covid-19 spread than previously thought.
However, Wilson said this had been a concern since the pandemic's inception, reinforced through cases such as the Covid-positive Rydges Hotel maintenance worker, whose infection in August hadn't been fully explained.
"This is all late in the day from my perspective, all these hotels should have had a rigorous review in terms of their ventilation systems from the very start," Wilson said.
Wilson saw the move as further proof hotels were not suitable to operate managed isolation. Instead, he said purpose-built facilities away from cities, possibly on military bases, would be much more effective.
"I think we should have been way more cautious and looked at hotel ventilation earlier on or really start moving away from the hotel quarantine model.
"Given that we think there's going to be long-term delays with getting everyone vaccinated, it's time to review this."
There are currently 83 returnees at the Grand Millennium, who will leave by Wednesday. The 141 returnees in the Grand Mercure will be required to have a day seven test and will leave by April 27.
A total of 652 MIQ rooms - equivalent to about 900 returnees - will now be empty as a result of the decision. However, Bliss said the New Zealand/Australia travel bubble, open today, was expected to free up between 1000-1300 rooms each fortnight.
"[The] Government is considering a range of options for the use of these rooms but, between this and our contingency, we're confident we can manage these two facilities going offline for a period," Bliss said.
He said the risk of transmission posed by ventilation systems was considered "very low" by health experts.