By Rowan Quinn for RNZ
The Government is being urged to stop using any hotels with sub-par ventilation for managed isolation so it can prevent Covid spreading between unwitting guests.
Health officials are investigating how the Northland woman whose case has sparked a major community response caught the virus from another guest - including whether it was through the ventilation system.
Auckland University professor of medicine Des Gorman said, though ventilation transmission was unlikely, it was possible because some hotels had systems that allowed droplets to spread to other rooms.
The government needed to employ ventilation engineers to investigate, he said.
"They should be called upon right now to have a look at the various hotels and identify those which are suitable and those which are not suitable," he said.
It should stop using any that could aid the spread, he said.
The government was already looking into some aspects of hotel air conditioning after a managed isolation outbreak in Brisbane suspected to have been spread by air con.
The Ministry of Health said it would look specifically at the Pullman's system to see if it could have played a role.
It was interviewing both guest in detail and was also considering whether the virus was spread through airborne particles in other areas, or from droplets on surfaces.
Infectious diseases expert David Murdoch said the cause of the latest infection may never been known but a thorough investigation of all possibilities was important.
That could lead to any vulnerabilities in the managed isolation system being uncovered and fixed.
And he supported the idea of taking any hotels out of the MIQ mix if they had ventilation systems that might aid the spread.
"While it may be difficult to prove one way or the other whether one particular system is linked to transmission ... having a well-maintained system that avoids circulating air to where there are other people certainly makes a lot of sense," he said.
And both professors backed the plan the government was considering to keep guests who had their final day-12 test separate from new arrivals to prevent infection.
They said everything practical must be done to make the isolation system as safe as possible.
Professor Gorman said many of the problems would be solved by having purpose-built facilities outside of highly-populated areas would be far safer and solve many problems - and it was not too late to build them, he said.
"This is not a bizarre and unusual event - we had SARS 1, SARS 2, we had MERS. This is simply the latest pandemic in a series of pandemics and I think we'd be incredibly naive to think when we get through this particular pandemic we're going to have a hundred years of happiness," he said.
The health ministry said it gave the government new advice on air-conditioning and ventilation next week but was not ready to share that publicly yet.