Although New Zealanders fleeing Victoria on green flights have been required to deliver a negative Covid test result before departure, the three days between testing and boarding the aircraft give them with ample time to pick up the virus - raising questions about how travellers from New South Wales will be handled.
Pauses in the trans-Tasman travel bubble still leave open the risk of infected travellers entering the country because of a timing gap between tests and departure.
From when the outbreak began in Melbourne just over a month ago, flights from Victoria into New Zealand were tightly controlled until last night when quarantine-free travel resumed at the same time
However, New Zealanders and others eligible to return on green flights from Victoria may still have been able to inadvertently bring the virus across the Tasman and into the community.
Now with a pause on quarantine-free travel between New Zealand and Sydney in effect as of midnight last night, plus reports of a Covid-infected tourist spending the weekend roaming Wellington, questions are being raised about the potential chinks in New Zealand's Covid armour.
Negative test results are as compulsory as passports these days when it comes to trans-Tasman travel, but the timing of the tests themselves has been a difficult quandary for the Ministry of Health.
The ministry required the test to be taken in the three days prior to departure, to make sure people will have their results back before they pack their bags and head for the airport.
“Any less time and there is a chance the results may not have come through before they’re due to depart,” said a spokesperson from the ministry.
However, they acknowledged there was a small risk people may catch the virus between test and departure - a scenario for which the only recourse is hoping travellers would show symptoms in time for Ministry of Health officials in New Zealand to notice upon arrival, or report their symptoms themselves.
As past situations have shown the country, relying on self-reporting is not a foolproof method of catching the virus - as evidenced by the ministry’s search for travellers who arrived from Victoria at the beginning of the pause who did not report themselves.
University of Otago epidemiologist Amanda Kvalsvig said the level of risk with this approach will be very strongly correlated to the level of risk in Victoria.
"If there’s unidentified transmission in Victorian communities, you would then be concerned that a traveller could test negative three days before their flight, keep moving about in their community, become infected and then bring that infection into New Zealand while they still feel well," she said. "In that case, airport screening measures aimed at identifying symptomatic cases would do very little to protect the New Zealand population."
The time spent between test and departure may be further lengthened if the test results do not arrive in time. In the event of a late result, passengers can reschedule their flight for up to 24 hours later, adding another day of potential contagion.
"If your negative test result does not arrive in time for your flight, you can reschedule your flight for no more than 24 hours later," states the ministry's website. "Even if this takes your test beyond the 72 hours before the scheduled time of your first flight."
The ministry said the risk was mitigated by other procedures in place at the border.
“People are asked to declare whether they have any symptoms at check-in and there is random temperature checking on arrival back in New Zealand,” the spokesperson said.
“And like everyone else, these travellers should follow the general advice that if they subsequently develop symptoms they should isolate, call Healthline and get tested.”
However, the Ministry of Health’s own website is quick to tell us Covid symptoms can take up to 14 days to appear.
“The virus can be passed on to others before they know they have it,” the website continues. “From up to two days before symptoms develop.”
The pause on quarantine-free travel to Victoria was lifted at midnight on Tuesday, after a five-day extension Minister Chris Hipkins called “in line with our precautionary approach”.
But travellers who have arrived on green flights over the last two weeks may still represent a risk - the only Covid test the Government has required of many of them occurred three days before they left a location where community transmission was still a valid concern.
Kvalsvig said sharing information across the Tasman is vital, as having a high level of awareness about the level of risk in Victoria and now New South Wales is New Zealand's first layer of protection.
"Given the very high transmissibility of the new variants that are circulating, it's likely that in a high-risk situation - if Victoria is seeing cases that aren’t linked to known outbreaks and aren’t already in quarantine - probably the only really effective way to prevent a New Zealand outbreak would be to close the bubble," she said. "It would be very disruptive to travellers’ plans and hopefully that response won’t be needed, but given the numbers of people travelling and how easily the new variants spread in public spaces, it would be very difficult to test our way to safety."
The ministry said another way it has endeavoured to keep New Zealand Covid-free is by requiring the ‘gold standard’ of tests from these travellers.
Those embarking on a green flight are required to take a PCR test (polymerase chain reaction test), which determines whether you are currently infected with the virus.
“Since travellers from Australia who have a negative pre-departure test can move freely around New Zealand, we want it to be the most accurate test available.”
Unfortunately, a PCR test does not tell medical officials if the person in question will be infected during the next three days.
