Patient transport ‘the weak link’ in NSW

Immunology experts say the patient transport between NSW quarantine ­hotels is the likely point of weakness in the system.

NSW Chief Health Officer Kerry Chant. Picture: Christian Gilles.

The mystery surrounding the “missing link” at the heart of the virus’s escape into the community has NSW health authorities racing to solve the puzzle, but immunology experts say the patient’s transport between quarantine ­hotels is the likely point of weakness in the system.

While two positive cases of the virus have been identified since Wednesday, NSW Chief Health Officer Kerry Chant said the decision to impose restrictions across Greater Sydney was predominantly because of an inability to explain the chain of transmission between hotel quarantine and the community.

“What we’re concerned about is that there is a missing link. We can’t find any direct link between our case, so what we’re concerned about is there is another person as yet unidentified that infected our case,” she said on Thursday.

On Wednesday, Dr Chant ruled out the “usual routes of transmission”, saying the man in his 50s had no apparent links to the hotel quarantine or border systems, nor had he returned from travelling overseas.

Genomic testing has linked the virus back to a traveller in the hotel quarantine system who returned from the US on April 26, but there aren’t any apparent links between the eastern suburbs man who tested positive and this case.

When pressed about whether health authorities had a working hypothesis about how the virus may have escaped into the community, Dr Chant said health officials remained in the dark about the point of transmission.

With the returned traveller having transferred from the ParkRoyal hotel in Darling Harbour to Special Health Accommodation after testing positive, Murdoch University professor of immunology Cassandra Berry said transporting infected patients was a point of weakness in the quarantine system.

“You have to take the patient out of an isolated area and move them into a patient transport vehicle with personnel. So you’ve got that movement from a confined space through the community into another area,” she said.

Professor Berry said while quarantine workers would be wearing protective gear, they may have been wearing it incorrectly or could have picked up residual virus that had been left on inanimate objects.

She said while not perfect, Western Australia’s quarantine system had already moved to mitigate this risk of transmission, leaving patients in one hotel unless they had to be moved to hospital.

With the man’s test indicating a high viral load, suggesting the infection was relatively new, NSW Health on Thursday added two ven­ues — Fratelli Fresh in Sydney’s CBD and Bondi Trattoria in Bondi Beach — outside his infected period as locations where the man in his 50s may have contracted the virus.

Health officials were reviewing CCTV footage from the moment the US traveller came into the system to ascertain where the leak may have occurred.

Dr Chant said investigators were following up quarantine workers who may have been absent, or not working everyday, to try to find the missing link.

UNSW global biosecurity professor Raina MacIntyre said another clear weakness in the hotel quarantine system were leakages that contributed to the airborne spread of the virus: “We’ve seen numerous instances where air from a room where they’ve been infected has travelled into the corridors and infected other people.”