Better border practices our best line of defence

Dr Eric Crampton
13 August, 2020

Even with the best of practices at the border, eventually something will get through. And something now has – though officials are still trying to figure out whether it came in with a passenger, or through refrigerated transport. But better practices at the border would reduce the risk.

If level 3 restrictions in Auckland cost about $1.5 billion in lost GDP per month – over and above the obvious costs everyone bears when schools are disrupted, shopping is difficult and social interaction is restricted – then erring on the side of spending too much, and being too careful in border protocols is the right approach.

It has been obvious for a while that border practices have a Dad’s Army flavour to them.

Last week, the government received a report suggesting that testing frontline border and managed isolation staff only once every two weeks might not be enough. When pressed by journalists, the report’s author, Professor Shaun Hendy, conceded people “shouldn’t be forced to take weekly swabs but strongly encouraged to do so” – to use a journalist’s paraphrase.

This is astonishing. In any sane system, agreeing to be tested regularly would be a condition of employment in the managed isolation and quarantine system.

Step back and think about how the current outbreak could have happened, if it came in with a passenger, and how a better system could manage those risks.

A returning Kiwi or other visitor was perhaps released from isolation but became infectious only later on. A small but real proportion of covid-19 cases take a long time to incubate.

In June, the government was releasing people from managed isolation without ensuring each person had returned a negative test result. It is possible that someone released in late June developed mild symptoms, infected others who developed mild symptoms, who then infected others who developed mild symptoms, who then infected the family that this week returned a positive test result.

If that is what happened, contact tracing will be a big job and Auckland’s level 3 restrictions could last a while.

Tightening up

Practice has since tightened up. The government is now requiring negative test results before anyone leaves managed isolation. But it is still possible that people who take a long time to develop symptoms will test negative before release, and only become infectious later. Even polymerase chain reaction (PCR) tests have a difficult time identifying positive cases if symptoms are still a few days away from developing.

That does not seem the most likely way the virus got out. But if residents in managed isolation soon to be released mixed with new arrivals, that is another way someone could leave isolation before becoming infectious.

The government could require everyone who leaves managed isolation to show up for one further test a week after leaving managed isolation. The government could require everyone who leaves managed isolation to turn on Google Maps location tracking and to share their movement history with contact tracing teams if required.

Those together would vastly simplify the task facing contact tracing teams.

The post-isolation test would mean that anything that did get out would be caught earlier.

And figuring out who needs to be contacted is much easier when Google can show where a person has been. I know I can’t on the spot remember everywhere I’ve been during the past week, and I do my best to use Rippl to check in. But here’s what Google Maps tells me I did last Saturday.


It caught the drive to drop kids off at various lessons, a stop at Harvey Norman (which reminds me I was also at Moore Wilson), a couple of op-shops we popped into on my as-yet fruitless quest for an old stereogram to gut for the library, a lovely walk around Brooklyn, one shop I definitely didn’t go to but which is near a Pokemon Go gym, and lunch at Curry Heaven. It effortlessly shows all this.

Turning on location tracking is free and easy. You can do it too. Google Maps Timeline is here. It isn’t perfect, but it remembers my movements far better than I can.

But back to policy.

Every traveller leaving managed isolation presents a small risk. That risk can be reduced through post-isolation testing and by helping the contact tracing teams. But there is also a risk with every worker in the managed isolation and quarantine system. Every worker on the airplanes delivering visitors to Auckland. Every bus driver shuttling visitors from the airport to their isolation facility. Every worker within those facilities who may be in contact with the isolated visitors.

Even with the best of personal protective equipment and facilities, safety protocols can still fail. Workers are human. The protocols must be checked to make sure they’re being followed and tightened up where necessary. Is every incoming visitor masked when getting on the plane all the way through to arriving in their managed isolation room? If not, why not?

But those protocols must also be augmented with frequent compulsory testing of workers in the system. New Zealand’s PCR tests are highly accurate, yet they are costly and can take time to return results. Saliva-based strip tests are cheap and fast, but only accurate for those with lots of the virus in their bodies. Daily checks with cheap and fast strip tests coupled with less frequent PCR tests could be an effective combination for managed isolation workers. That frequent testing would not stop a worker from passing the virus to a close contact. But they would catch it quickly.

Why does that matter?

Right now, the public health system is puzzling out where the Auckland outbreak came from. They must figure it out to know who needs to be tested. The current case has no known links with any managed isolation workers or recent travellers. That means there is at least one “hop” between the case that got out and the case that was found. There could be more. If there are more, the contact tracing task becomes much harder. It becomes far more likely that only level 3 or level 4 restrictions could get things back under control. Regular testing of workers limits that possibility by catching any infection before a worker can infect others.

Weighing up the cost

If a month in level 3 costs Auckland $1.5 billion in financial terms, plus added misery, but each strip test costs about $10, each Aucklander could be tested a hundred times before hitting the financial cost of that month in level 3.  And only workers in the managed isolation system need regular testing.

A full-bore cost-benefit assessment isn’t needed to start doing this. It is almost incomprehensible that the system considers regular testing of staff an “aspirational” goal. The prime minister said in yesterday's press briefing that asking every worker to undergo a daily swab test is unreasonable. But inadequate testing that leads to a new level 3 lockdown is even more unreasonable. And there are options sitting between irregular and daily swab testing.

Finally, the government must create an incentive for the workers to be tested.

Anyone who has gone in for covid-19 testing should self-isolate until results return. Test results may come back quickly, or they may take a while. Both of my children have been tested, as has my wife. It took about two days for results to come in.

We are lucky. Our employers let us work from home in those circumstances. Not everyone can. And using up a chunk of one’s available sick leave for what may be just a cold is not particularly appealing. Early on, the government’s covid-leave payment was available for employers with self-isolating workers. That support system ended on March 27 when things were rolled into the wage subsidy scheme, though the prime minister yesterday said a leave payment is available for close contacts who have been asked to self-isolate.

The government could compensate employers for providing extra days of sick leave for self-isolating workers awaiting test results. For the past month, officials have urged people to be tested if they develop symptoms and worried about the declining number of people presenting for testing. But they have not looked to the financial disincentives that bar many workers from being tested, even when the tests are free. This must be remedied.

The border is the first and most important line of defence. It needs to be strengthened. The costs of strengthening it pale in comparison to the costs of weaker defences.

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