March 13, 2021
Dr Rawiri Taonui Covid Maori | Up to 85.7 percent chance of further OutBreaks
As we embark on the largest mass vaccination in our history, there is a 34.4% chance each week and an 85.7% chance each month of a community outbreak unless we reduce the number of arrivals into New Zealand. A reduction should focus on the 36.4% of arrivals who are non-New Zealand citizens and/or the 40.9% who are non-permanent or not intended long-term residents. After worldwide reports of fraud, we also need to revaluate the pre-departure negative test regime required to cross our border.
Vaccines vs Variants
Over the next nine months, New Zealand will walk a tight rope between the salvation of anti-Covid serums, control of Covid-19 at our borders and in Managed Isolation and Quarantine (MIQ), and the threat presented by hyper-infectious variants now sweeping the globe.
New Zealand is currently delivering the Pfizer-BioNTech vaccine into the arms of 55,000 heroic frontline workers and their families. Vaccination of the public will begin in April/May. From there, it will take at least until the end of the year before New Zealand has confidence that we have reached the 70% to 80% population threshold required to achieve herd immunity.
Probability of Community OutBreak by Average Weekly Arrivals
The following charts examine the number of border entries and active cases in MIQ and the relationship between those numbers and failures and breaches at the border and in MIQ leading to outbreaks in the community. The methodology employed was used to predict last year’s Auckland OutBreak and the Pullman (North, Auckland, Hamilton) and Papatoetoe clusters.
The following bar chart below shows the number of entries into New Zealand by calendar week beginning 8 June, the day after the last case in the first wave recovered.
The chart tabulates:
- The number of weekly arrivals into New Zealand (red and blue vertical bars) is a primary indicator of pressure on the border, MIQ and the workforce. High numbers in MIQ, whether Covid positive or negative, create more points of management, interaction, and potential transmission that in turn increase the risk of a failure/breach leading to an outbreak in the community.
- Breaches at the border/MIQ into the community (red descending arrows) enable estimating the probability of future outbreaks. Where known, the date of infection is shown rather than the date when the case was announced, for example, the AmeriCold case, the first in the August Auckland OutBreak announced on 11 August, was infected around 27 July.
- The number of weeks where breaches occurred (red vertical bars) also facilitates the calculation of future outbreaks.
- Significant clusters that developed inside MIQ (blue descending arrows) represent periods of heightened risk.
- The date when the Kent (British) B117 and South African B1351 variants arrived in New Zealand (black descending arrows) signal heightened risk. B117 is likely more infectious than B1351. B117 also has a different symptom set to earlier strains, possibly higher infectivity among young people and may have a higher fatality rate. The B1351 strain is probably less infectious than B117 but more infectious than earlier strains. B1351 can evade some human antibodies causing reinfection in people who might otherwise have been immune after recovering from an earlier strain. Vaccines are generally less effective against B1351.
- The red safety line (red horizontal line) shows that all but one border/MIQ breach occurred when arrivals exceeded 300 per day or 2,100 per week. There have been no border/MIQ breaches below this line since late July. Below 2,100 entries per week is safer, above 2,100 is higher risk.
There have been 16 failures/breaches from the border/MIQ into the community. The first two, the British Duo and the Stamford case can be discarded because the process and security issues causing those events are now much improved.
Since 8 June 2020, entries into New Zealand have averaged 380 per day or 2,670 per week. There have been 14 failure/events during 11 of 32 weeks since late July. Projected forward, this gives a 34.4% chance each new week of another failure/breach event if entries continue at current levels.
The following chart shows the total entries per month since April (vertical bars), divided by seven to show the average weekly trend of arrivals (purple line). Months, where border/MIQ failures occurred, are shown (red bars).
There were border/MIQ failures/breaches in seven of the last eight months. Projected forward, each month has an 85.7% probability of a breach occurring if we maintain the current level of entries. The Air New Zealand case reported on 7 March confirms we already have another breach.
Active Cases in MIQ
The number of active cases in MIQ provides an additional lens for assessing the risk of further outbreaks. The chart below shows the average daily number of active cases each week in MIQ, the arrival of the new variant strains, the 14 failures/breaches since June and a line of risk at 30 active cases in MIQ (red horizontal line). When the average number of active cases in MIQ is above 30 per day, there is a higher risk of an outbreak. When below 30, there is less risk.
The two earliest events, the Americold and Rydges cases occurred below the risk threshold of 30 active cases per day when MIQ processes and security were still being developed. Border and MIQ protocols have since been significantly strengthened. While they are linked to a surge in border entries (above), they are less relevant to the active MIQ metric.
The remaining 12 breaches/failures occurred when active cases in MIQ were above the 30-case threshold. Driven by a massive worldwide surge in new Covid-19 cases, culminating in a peak of 850,000 new cases per day in early January, active cases in our MIQ grew from 15 to 25 per day in August to a one-day peak of 85 on 18 January and that week an average daily high of 77 leading to the Northland, Auckland, Hamilton, and Papatoetoe events. Controlling risk to the community means reducing active cases in MIQ.
A more recent international decline through the end of January to mid-February mirrored itself in a decline in positive cases in MIQ to 50 per day during the week beginning 15 February. Since then, positive cases have begun an incremental increase to an average of 68 per day well. Well above the 30-case threshold, further border/MIQ breaches/failures are likely.
The Inevitability of the Pullman and Papatoetoe Clusters
The number of arrivals per month into New Zealand grew steadily from 6,400 in April 2020 to a peak of 13,000 entries in January this year. With the shorter 28-day month, total arrivals in February were lower, but the average 3,070 weekly rate the highest since April last year (purple line chart 2).
This peak coincided with three key events. Firstly, the massive worldwide increase in new cases between October and January. Secondly, an increase in the average number of active cases in MIQ from 15 to 25 per day before August to 70 to 80 per day in January. And thirdly, the arrival of the Kent B117 strain in New Zealand on 13 December followed by B1351 13 days later.
The combination of increasing border entries, higher active cases in MIQ, the international surge and the arrival of two variants made the Pullman B1351 Cluster and the Papatoetoe B117 Cluster inevitable. Of the six events this year, the variants caused three within 21 days of each other, Northland B1351 (24 Jan), Auckland B1351 (27 Jan) and Papatoetoe B117 (14 Feb). More events are likely.
Reducing Numbers and Citizenship
In January, the Iwi Leaders National Pandemic Response Group and the Te Kahu o Taonui northern tribal collective made recommendations to the government to reduce numbers entering New Zealand, such as reducing the number of foreign workers and students. In February, Professor Michael Baker and Associate Professor Nick Smith from Otago University and Senior Lecturer David Welch from Auckland University added to that call, for example reducing numbers from at-risk countries.
The Prime Minister responded saying that New Zealand Citizens have a right to return home and barring their return would render them stateless. No one has suggested barring entry by New Zealander citizens. Rather, the recommendation is that we reduce the overall number of arrivals to protect New Zealanders at home.
Data from the New Zealand Customs Service (NZCustoms) and Statistics New Zealand (StatsNZ) indicates ample room for manoeuvre without infringing on the rights of New Zealand citizens. The data shows that 41,814 or 36.5% of 114,516 entries between April 2020 and February 2021 were non-New Zealand citizens.
And according to figures from StatsNZ, 36,138 or 40.9% of 88,434 entries between April and December 2020 were not current or intending permanent or long-term residents. This includes, for example, the American Magic and UK INEOS Americas Cup teams who brought 420 people into New Zealand, including 232 non-competing family members. A reasonable measure would have been to limit entry to competitors only.
Reducing numbers could include non-New Zealand citizen non-permanent persons from high-risk countries and/or non-essential workers, foreign works, students, sports teams, and others visiting New Zealand for non-compassionate reasons. We have already seen clusters form inside MIQ from three groups of Russian mariners (2) and the Pakistan Cricket Team, one of which led to infection among MIQ staff in Christchurch.
The Pre-Departure Negative Test Requirement and Day Zero Test
Questions should be asked about the integrity of the pre-departure negative test required for entry into New Zealand. The requirement for a negative test within 72 hours before departure and evidenced by a ‘written form, certified by a laboratory or another form of approved evidence’, came into force for flights from Britain and the USA on January 16. This extended to all countries except Australia, Antarctica, and several Pacific Island nations, on 26 January.
The change accompanied an additional ‘Day Zero’ Covid-19 test introduced on 1 January and extended on the same basis as the pre-departure test from January 18.
Most countries now require evidence of a negative test before entry. Since October, there has been an increasing number of reports across the world of fraudulent negative certificates. Last week, the European Police Agency (Europol) reported multiple instances of fraudulent certificates being sold at airports and online in Britain, France, Spain, and the Netherlands. Reports from Heathrow Airport say they are detecting fraudulent certificates every day. Fraud has also been reported in South Africa, Israel, Canada, Brazil, and Mexico. During one January weekend, 45 people tried to enter Croatia with fake test certificates. One forensic researcher reported that over 100,000 people had joined a Telegram site offering fraudulent certificates.
One of the key problems with the requirement is the absence of a standard form, language or encryption technology, without which, airports like Heathrow report that ‘It is almost impossible to tell whether a certificate is fake or not except by going through a lengthy almost impossible verification process’.
New Zealand Situation
There are grounds for suspecting fake testing documentation has occurred in New Zealand. The 53-member Pakistan cricket team entered the country in October with negative certification. Subsequently, 14 tested positive for Covid-19; eight were deemed historical, six were active cases.
Also, in October, a group of 137 Russian and Ukrainian mariners arrived in New Zealand to work on fishing vessels. Although subject to pre-departure negative tests and 14-days self-isolation, 31 tested positive upon arrival in New Zealand, resulting in two workers in the Sudima quarantine facility becoming infected. In January this year, 17 cases of Covid-19 were discovered in a second group of 190 mariners from Russia; nine were historical cases, eight were active cases.
According to Customs New Zealand, there were 11,183 arrivals on flights subject to the negative test requirement to 9 March, 10,700 were compliant, 440 such as infants or people with medical conditions were exempt. Thirty-nine received warnings and infringement notices for not meeting the required standard. The latter requires explanation.
An examination of arrivals on flights raises concern. There is an increasing prevalence of passengers arriving on the same flights from the same country, supposedly with valid negative tests, testing positive immediately upon arrival. For example, On 13 February, five passengers on the same flight tested positive upon arrival. Flights of concern include at least two from the USA, three from Britain and seven from India. Other flights of concern are from Brazil, Japan, and Ethiopia.
Testing positive after arrival can be expected, for instance, where a person becomes infected immediately before or after they take the pre-departure test. They might also get infected in transit. However, when multiple arrivals from the same flight test positive on Day Zero the probability exists that they were infected before the 72-hour pre-departure testing period.
The issue appears to be occurring with greater frequency and numbers. Four people from one flight tested positive upon arrival on 2 March. Two days later, nine did so, and two days after that another seven. At the time of writing, 88% of the last 40 positive cases to arrive tested positive on Day Zero or Day 1 of which 20 arrived on just three flights.
The writer has also spoken with travellers and industry operators. The majority describe inspections at the point of departure as lasting no more than a few seconds. No one reported an airline checking their details with a laboratory.
One of the weaknesses in our system is that the Ministry of Health accepts, PCR, LAMP and antigen tests, and home tests, the latter carrying no guarantee that the sample, which must be tested by a laboratory, is from the person who submitted the test. Moreover, the antigen test, usually a rapid saliva test, is accepted for entry to New Zealand but rejected as beneath the ‘gold standard’ for border and community testing inside the country.
China is possibly the only country to operate a successful negative test requirement regime because intending passengers must pre-book their tests from one of more than 700 embassies and diplomatic offices around the globe. Countries like New Zealand with less than 40 diplomatic missions do not have that capacity.
One solution is to encourage greater scrutiny from airlines. A person arriving in New Zealand without evidence of a negative approved test is liable to an infringement fee of $300 or a fine of up to $1,000. However, if a passenger arrives in Britain without proof of a negative test, they can be fined Â£500, and the airline also fined Â£2000.
The main solution appears to be digitally encrypted unalterable travel passes, test or vaccine passports. China has adopted the world’s first virus passport. Singapore is introducing a new Travel Pass from the International Air Transport Association Travel Pass. Israel and the European Union have announced their intention to follow suit. American Airlines, British Airways and United Airlines have introduced apps that hold unalterable health testing data. Our officials have spoken to this eventuality but concerningly remained mute on the issue of fraud both in New Zealand and overseas.
Leadership and Systems
There are mitigations. New Zealand has good leadership. Prime Minister Jacinda Ardern has been inspirational. Her decision to go to an Alert Level 4 lockdown on 25 March 2020 when the country had just 205 cases allowed the Team of Five Million to defeat the first wave in 100 days. Minister of the Covid Response Chris Hipkins is exceptional during emergencies. The Director-General of Health, Dr Ashley Bloomfield, is culturally and policy conservative but astute and assiduous.
We have a world-class testing and genomic sequencing regime; we are one of few countries to sequence all positive cases. Our contact tracing and isolation system and Covid-19 app are equally world-class. In most instances, our systems will detect and ring-fence outbreaks. But for how long? The Papatoetoe outbreak could have taken a quite different path if Cases A and B had gone to Waitangi on 6 February instead of New Plymouth.
An Improving World Situation
A recently improved world situation assists our cause. The number of daily new cases recently dropped from the 850,000 January high to pre-surge mid-October levels of about 480,000 per day, although we should not be complacent with another incremental increase creeping towards November levels.
The result of stronger lockdowns and 345 million vaccinations administered since December, now averaging 8.7 million per day across 121 countries, fewer daily new cases translate into less pressure on borders.
Reducing Border Numbers and Active Cases in MIQ
During the nine-month race to vaccinate, there is a 34.4% chance of a breach each new week, an 85.7% chance of a breach each new month. For the most part, our systems will contain these as small events. Nevertheless, the risk remains of a larger outbreak event. The arrival of the British B117 and South African B1351 exacerbate that risk. Unless we control numbers at our border and active cases in MIQ, the new variants will continue to pepper and pierce our borders as we race a fine line between vaccines and variants toward herd immunity.
Noho haumaru – stay safe and self-sovereign.
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