Australia and Pacific nations have been mentioned as bubble border buddies, but what other countries pose a low-enough risk to consider bubbling with?

After almost a month with no new infections, New Zealand’s winning streak was broken by two cases brought in by overseas travel.

The travellers, from the United Kingdom, were allowed to leave managed isolation unsupervised for a family funeral. Health officials said it was an oversight that would be rectified in future.

Border controls for returning New Zealanders have recently been updated. All arrivals are tested and there are no longer exemptions granted for funerals without a negative test.

The breaking of our 24-day run of zeros highlights that while life feels back to normal for some New Zealanders, overseas the virus still rages with thousands of new cases confirmed each day. 

Border controls are the key defence against any fresh outbreak, but they’re also a choke-point. 

Currently New Zealand has the capacity to house 3200 arrivals at a time in quarantine or managed self-isolation for two weeks. As Newsroom’s Bernard Hickey reported, this works out at 250 a day. It barely scratches the surface of the number of New Zealanders wanting to come home, or people with temporary work visas who were trapped abroad when the border closed.

For the tourism sector, the outlook is grim. There’s no capacity to make the case for tourists to go through the same two-week system of managed isolation. Even if there were capacity, the idea of being stuck in a room for two weeks will likely be off-putting.

What could the criteria be for reopening borders without the two-week stint in isolation, and which countries should top the bubble buddy list?

Some countries have never had, or at least never reported, a case of Covid-19. These include the Cook Islands, Kiribati, Marshall Islands, Micronesia, Nauru, Niue, North Korea, Palau, Samoa, Solomon Islands, Tonga, Turkmenistan, Tuvalu and Vanuatu.

Due diligence for buddying up

University of Otago’s Professor Michael Baker and colleagues have written about how elimination could be scientifically quantified. Eliminated status could then be used to help countries decide whom to open their borders to.

Baker said confirming elimination status is work the World Health Organisation does for other diseases such as polio, measles and rubella. It just hasn’t been done for Covid-19 yet.

“It’s a well-worn path. It’s just this is a new virus and very few countries have eliminated it. Or even have that [elimination] as their goal at the moment.”

He said there were three components that could be considered when defining elimination.

“There would be an absence of cases for a certain period, the presence of a high-performance surveillance system and exemptions for people who arrive in the country and are safely quarantined.”

A set of criteria such as this might remove some countries that may have never reported cases, but at the same time can’t prove they’re testing comprehensively. 

“You just need to go through a process of working out what you regard as an acceptable standard to reach. It’s kind of a due diligence process.”

He said the process for border control and elimination status is perhaps best established by veterinary biosecurity, “where you require proof of elimination from other countries before you might allow their products in”.

28 days later

To be 95 percent certain a country has eliminated Covid-19, one study estimated there would need to be 27 to 33 days with no new case. At present, the Ministry of Health closes clusters after 28 days.

In the 28 days without a case club – May 19 to June 15 – are Anguilla, Aruba, British Virgin Islands, Brunei, the Faeroe and Falkland Islands, Fiji, French Polynesia, Guernsey, Laos, Liechtenstein, Montserrat, Papua New Guinea, Saint Lucia, Seychelles, Saint Maarten (the Dutch part), Tanzania, Timor, and Turks and Caicos Islands.

What about Australia?

The much-mentioned Trans-Tasman bubble could be some time away. In the same 28-day time period, Australia had 275 cases of Covid-19. A modelling study completed by Baker, professor Nick Wilson and professor Martin Eichner looked at what could happen if New Zealand and Australia bubbled together. The study is yet to be peer-reviewed.

Their modelling was based on one flight a day from Australia and a low prevalence of the virus. 

Quarantine, mask-wearing on flights and screening remained the most effective measures to reduce outbreak risk.

Exit and entry screening, masks on aircraft and two PCR tests, self-reporting of symptoms and contact tracing, and mask use by the passengers until the second PCR test, reduced this risk to one outbreak every 29 years.

With just mask use by arrivals for 15 days, the risk was one outbreak every 14 years. After hearing of the two new cases yesterday in New Zealand, Baker pointed out most countries’ mask use would be mandatory for the entire 14-day period. 

Without quarantine, or any measures in place, an outbreak was estimated to occur after an average time of 1.7 years.

Statistics New Zealand numbers show in 2019 more than 1.5 million visitors from Australia came to New Zealand.

Of countries with zero cases for the past 28 days, only Pacific nations make it onto Statistics New Zealand’s top 41 list of countries people visit from. The total combined number of visitors from Fiji, French Polynesia, Tonga, Vanuatu and Samoa for 2019 was 117,964.

University of Otago’s Wilson suggests New Zealand could help Pacific nations establish their Covid-19 elimination status.

“This might require New Zealand offering support to verify their Covid-19-free status with serosurveys (widespread antibody testing) or other verification processes. But these nations should be the first nations for New Zealand to work with for open travel arrangements – probably ahead of Australia, which still has uncontrolled pandemic spread.”

Half-way there at 14 days

There’s another batch of countries at the halfway point of zero cases for 28 days.

These include Equatorial Guinea, Greenland, Isle of Man, Monaco, Montserrat, Northern Mariana Islands, Saint Kitts and Nevis, and Western Sahara.

These countries are also not on the Statistics New Zealand list. As of June 15, Taiwan was one day away from making the cut. Baker describes the country as one that has “done everything right, right from the beginning”. Last year, 53,453 visitors came to New Zealand from Taiwan. 

A long way to go

Other countries are a long way from bubble consideration with uncontrolled spread. Of the below countries, which have had more than 10,000 cases in the past 28 days, 15 make the Statistics NZ top 41 list. Last year they accounted for 848,921 visits to New Zealand.

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