Less than one per cent': WA's Chief Health Officer under pressure to justify border closure during Palmer court fight
Jul 31, 2020
By Heather McNeill
WA’s Chief Health Officer has come under pressure to explain why the state refuses to open its border to the five other Australian jurisdictions that have eliminated community spread of coronavirus.
During Clive Palmer’s challenge to the legality of WA’s hard border, being heard in the Federal Court, evidence given by five expert witnesses revealed the risk of COVID-19 re-entering the state would remain at less than one per cent if the border was reopened to all but New South Wales and Victoria.
Premier Mark McGowan has previously said his legal advice was to take an all-or-nothing approach to reopening the border, however since those comments, every other jurisdiction that had its borders closed has moved to reopen to states that are on top of the virus.
Chief Health Officer Andrew Robertson conceded there was little public health justification for keeping the border closed to South Australia, the Northern Territory, Queensland, the ACT and Tasmania, which had eliminated community spread.
Asked by Commonwealth Solicitor-General Stephen Donaghue QC if his advice to keep the border closed was based on an assumption he had to work on and all-or-nothing approach, Dr Robertson agreed – revealing he had written to the state government suggesting it consider a travel bubble with SA and NT, but did not hear back.
“If I can either open to all or none, and not to some, then obviously I have to work within those parameters,” he said.
“[If we opened to some jurisdictions] there is the risk of border-hopping and we’ve seen that on a couple of occasions including international flights.
“But the other risk is that you would then become dependent on the decisions of another state for them opening their borders, so if they opened their borders, then people could pass through the state into your state without restriction.”
Mr Donaghue suggested with around 1600 travellers in hotel quarantine and – prior to the border clamp-down with Victoria – around 3300 people arriving from interstate each week, WA was willing to accept some risk the virus could return, and asked whether that risk would be increased by opening to other COVID-19 free areas.
“While everybody recognises the reintroduction of COVID-19 in Western Australia would be a serious thing, the reality of the matter is that even with the border direction, that risk exists in an appreciable way,” he said.
A probability table created by epidemiologist Tony Blakely estimated the chances of a person from NSW flying into Perth with COVID-19 and causing an outbreak in any given month was four per cent, which then reduced to 0.18 per cent if quarantine and testing measures were put in place.
The figures were based on 41,000 travellers arriving each month, which represented 50 per cent of pre-COVID travel levels.
Dr Robertson did not agree with some of the assumptions made in the scenario, however WA had no comparable modelling.
Fellow expert witness, Associate Professor Kamalini Lokuge, said modelling in this scenario was unhelpful due to the evolving nature of the disease.
Asked if it would be more appropriate to ban travel into WA from coronavirus hotspots, rather than a blanket ban, Dr Robertson said the five to seven day lag to understand how the virus was spreading created an unknown risk.
"The reservation with hotspots is they are reflective of what's been happening with the disease five to seven days previously," he said.
"We're looking backwards in time, so to get ahead of it, if you just concentrate on hotspots you are well behind where the actual epidemic is and we've seen that illustrated very clearly in Victoria where the number of new hotspots was being added to daily."
Dr Robertson said the risk of the disease returning could never be fully removed, adding the state was considering stricter measures for truck drivers entering WA to have to wear masks and get COVID-19 tests, given the cohort was one of few exempt from border and quarantine requirements.
He said hotel quarantine procedures had also been reviewed in light of three guards becoming infected since March.
“We have whole flights that come in with nobody being infected and we have flights coming in with 20 or 30 people on board that become infected,” he said.
Other public health experts giving evidence during the trial including Professor Blakely, Professor Peter Collignon, Associate Professor Sanjaya Senanayake and Associate Professor Lokuge, said the risk of COVID-19 being re-introduced in WA would remain extremely low if the border was reopened to other eliminated states, and if surveillance and testing systems remained strong.
Professor Lokuge said a one per cent risk was still too great from a public health perspective, but that the risk would not be increased if WA opened its borders to other elimination states, as long as the the other border rules were the same as in the west.
"While you have the risk of importation [of coronavirus] it's only border measures that will prevent that. Other measures are, to different degrees, only effective in preventing spread if importation occurs," she said.
Each expert agreed all borders should remain closed to Victoria.
WA has been guided by a precautionary principle to the virus, however Professor Lokuge said she believed the approach was inconsistent given authorities were allowing 4000 people into the state each week, and 30,000 people to gather at Optus Stadium.
"I personally would not [allow fans at the stadium]," she said.
Queensland-based Mr Palmer, who was denied access to WA in May, claims the closure is unconstitutional as it restricts the rights of Australians to move freely between states.
Western Australia Premier Mark McGowan says 'people will die' if Clive Palmer wins his High Court bid to reopen the state’s border.
Section 92 of the Commonwealth of Australia Constitution Act states, "On the imposition of uniform duties of customs, trade, commerce, and intercourse among the States, whether by means of internal carriage or ocean navigation, shall be absolutely free".
That movement can be restricted in the event of a public health emergency.
Judge Darryl Rangiah said his task would be to determine whether the border closure was reasonably needed to contain the spread of coronavirus, and what the consequences of reopening it would be, including a potential outbreak in WA.
WA Premier Mark McGowan closed the border on April 5 to prevent undetected coronavirus cases from entering the state. WA has not had a case of community transmission in more than 100 days.
He has labelled Mr Palmer a “menace to Australia”.
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