Each of the nine new cases arrived at Auckland International Airport, and all are now isolated. Photo: Getty
Each of the nine new cases arrived at Auckland International Airport, and all are now isolated. Photo: Getty

ScienceJune 23, 2020

Siouxsie Wiles: Why are we seeing these new cases of Covid-19 in New Zealand?

Each of the nine new cases arrived at Auckland International Airport, and all are now isolated. Photo: Getty
Each of the nine new cases arrived at Auckland International Airport, and all are now isolated. Photo: Getty

Anxiety is totally understandable, and there have been a few own goals. But what we’re seeing is no great surprise, and it’s no time to panic, writes Siouxsie Wiles.

After weeks of no new cases of Covid-19, in the last week we’ve recorded nine. That’s sounds pretty scary, but here’s why there’s no reason to panic.

For weeks now, almost every day there have been over 100,000 new confirmed cases of Covid-19 around the world. On two days last week that number topped 170,000. Sadly, it looks like the pandemic is accelerating. The director general of the World Health Organisation, Tedros Adhanom Ghebreyesus, has warned that the world is in a “new and dangerous phase”.

Yet here in Aotearoa we are at alert level one. We even had several weeks with no new cases. It was a great sign that all our hard work had paid off and our elimination strategy had succeeded.

Then came the news that two New Zealanders returning from overseas had tested positive. This wasn’t a surprise to me. With the pandemic not only raging but accelerating, we should expect to pick up cases at the border. This is why we have a 14-day managed isolation process in place. The more interesting question is: why didn’t we see any cases at the border in the few weeks before? I’ll come back to that.

Of course, the news last week wasn’t just that we had two new cases of Covid-19. It was that the women had left managed isolation without being tested and travelled from Auckland to Wellington. All while possibly having the virus. Naturally, that has led to lots of people getting very anxious that the women might have transmitted the virus to others, and we’ll all be back in alert level three or four before we know it. The reality is, there is very little chance they’ve transmitted the virus to anyone other than the person they were given compassionate leave to visit. And yes, that’s counting the brief contact they had with friends while trying to find their way out of Auckland.

What didn’t help people’s anxiety was the Ministry of Health saying that they are following up hundreds of contacts as a result of the positive cases. That was a complete own goal. Many of those contacts aren’t contacts at all. They were people on the same flights or staying at the isolation hotel. In other words, they are all people who could easily be positive anyway because they have come from overseas.

What the debacle did show us is how important it is that we have good processes in place for identifying and controlling cases at the border. We all thought those processes were watertight. It turns out they weren’t. Now we know and the holes are being plugged, which is exactly what is needed. Because the way this pandemic is going, our border controls are going to be needed for quite some time. Like any plan, you often don’t find its flaws until you test it.

What’s with this flurry of new cases?

As I said earlier, I’m surprised we had such a long run with no cases. Especially given people have been coming into the country from overseas. After the initial rush to get home in February and March it’s likely that had slowed to a trickle. Now that we are in alert level one and planes are starting to fly again, the numbers of people able to get home is probably increasing. Where they are coming from and the levels of community transmission in those countries will also play a big part in how likely they are to be coming home with Covid-19. Remember, people can incubate the virus for about two to 10 days, so they could hop on a plane feeling absolutely fine only to develop symptoms when they arrive.

Until recently, there hasn’t been routine testing of people coming home and into managed isolation. People were only tested if they had symptoms or perhaps had had contact with someone with symptoms. That would suggest then that the people who have been coming home either haven’t been infected, or haven’t had symptoms, or have had mild symptoms they’ve mistaken for something else like asthma.

People also haven’t been routinely tested before they left isolation after their 14-day stay. Judging by the posts I’ve seen on social media that’s freaked some people out a bit. It’s worth remembering that it’s the 14-day isolation that’s the important thing here. Once those days are up and people haven’t displayed any symptoms the evidence so far would suggest they aren’t a risk to anyone. I haven’t seen any evidence that says people become long-term asymptomatic carriers of this virus.

An important part of managed isolation is that people must not be able to somehow get infected during their 14-day stay. That will be one of the reasons why people with symptoms are moved to a dedicated facility. But it’s also why people that have come into the country on different days and on different flights shouldn’t be allowed to hang out together. It sounds like there’s been a bit of that going on and that absolutely has to stop.

The procedure now is that people coming into the country will be tested twice – three days into their isolation and then again before the 14 days are up. Lots of people have been asking why people can’t just get tested before they get on a plane or as soon as they arrive. They can. But a negative test doesn’t mean people aren’t infected. They could be in the incubation period. Or the swab might not have picked up enough viral material. That’s why testing multiple times during isolation is a good idea. But its also why the 14-day isolation is still the key. Given this is a virus that spreads before people know they have it, isolation is our best line of defence.

As the pandemic grows around the world, people will want to come home. And they have every right to do so. With mandatory isolation, we have an excellent way of stopping the virus from spreading to the wider community again. What we have to remember is that mistakes do happen. That’s why we should still use the Ministry of Health’s contact tracing app and keep records of where we’ve been and who we’ve been with. And we should definitely ask, without hesitation, to get tested if we have any of the symptoms of Covid-19.

Keep going!