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A Covid-19 testing station in Wellington (Photo by Lynn Grieveson/Getty Images)
A Covid-19 testing station in Wellington (Photo by Lynn Grieveson/Getty Images)

ScienceJune 23, 2021

Siouxsie Wiles: Why the Covid-19 weekend in Wellington is so serious

A Covid-19 testing station in Wellington (Photo by Lynn Grieveson/Getty Images)
A Covid-19 testing station in Wellington (Photo by Lynn Grieveson/Getty Images)

How did we get here, why is the alert level change necessary, and could this all have been avoided?

After several scares, it’s finally actually happened. What is likely to be the uber-infectious delta variant of Covid-19 has hitched a ride to Aotearoa. It’s come via a visitor from Sydney who took advantage of the trans-Tasman bubble to spend the weekend in Wellington and visit the surrealist art exhibition at Te Papa. As a result, from 6pm tonight, Wellington, the Kāpiti Coast, and the Wairarapa will move to alert level two.

How we got here: Sydney’s growing Bondi cluster

A week ago, on Wednesday June 16, health authorities in New South Wales announced that someone who works as a driver transporting international flight crews had tested positive for Covid-19. Later that day their household contact also tested positive. The two cases had visited a number of places including the Westfield at Bondi Junction. The next day, another two people tested positive, one of whom had visited the same cafe as the first two cases. By Sunday, there were 10 cases, almost all linked through the Westfield mall or close contacts who were already in isolation. As of today, the Bondi cluster has grown to 31 cases. Four cases currently remain unlinked. 

As we’ve seen so many times before, the virus has transmitted predominantly to close contacts, especially those living in the same household. It’s also passed through a birthday party, where eight of the approximately 30 attendees have now tested positive, including a two-year-old. It’s also passed between strangers, including two people who momentarily walked past each other in the Westfield mall. That’s how potentially infectious this delta variant is.  

Moving Wellington to alert level two

Thanks to their use of our Covid Tracer App, we know our visitor from Sydney stopped off at a lot of places during their stay, including the types of venues that are ripe for a superspreading event. This includes an evening spent at a bar, as well as the very busy surrealist art exhibition at Te Papa. That does mean quite a lot of people in Wellington will have potentially been exposed to the virus. What we don’t know of course, is how infectious the person was when they were out and about. They’d had their first dose of the AstraZeneca vaccine, which may mean they were less infectious than they could have been. But we do need to brace ourselves for the possibility that this one case may result in many others.

The New Zealand government is still pursuing an elimination strategy with Covid-19. In the first instance, they will try to control the virus using the test-trace-isolate strategy – identifying those who have been exposed and getting them tested and into isolation to stop any further spread. That’s why it’s so important for anyone who was in Wellington over the weekend to check the Ministry of Health’s list of locations of interest and follow the advice about isolating and getting tested. And even if you weren’t in Wellington, if you have any symptoms that could be Covid-19, please arrange to get tested.

Read this chart in a range of languages here.

Moving Wellington to alert level two is another tool in the toolbox which will hopefully help reduce the chances of further transmission. One thing we have to keep in mind though, is that our alert levels were put in place before the more infectious variants of the virus evolved. While level two does put a limit on gathering sizes, it still has quite an emphasis on maintaining physical distancing as a way to reduce spread and this is unlikely to be as effective as it was before. After all, this virus is airborne. If you are indoors, especially in a poorly ventilated space, keeping two metres away from others is unlikely to offer much protection. Much better would be for us all to be wearing masks when indoors, at least in venues where we aren’t eating and drinking. 

Could this all have been avoided?

A lot of people are asking me if this could have been avoided, by for example, adding pre-departure or on-arrival testing to visitors coming from Australia, or by pausing the trans-Tasman bubble earlier, or by speeding up the vaccine rollout. It is certainly a good question. 

I am disinclined to criticise our vaccine rollout for two main reasons. The first is that we are at the mercy of vaccines being delivered and, quite frankly, there are people around the world who need those doses far more than we do at the moment, so I am happy for us to wait. Even so, we will all be vaccinated long before many healthcare workers or vulnerable people in low-income countries will be. That is appalling and just one of the reasons why this pandemic will keep going for some considerable time. If you have $10 to spare, please consider buying a vaccine dose for someone less privileged. The second reason is that the vaccine rollout is no easy task. I am so grateful to everyone in the health system and beyond who has been working behind the scenes to get everything ready for what is the biggest vaccine rollout in our history. 

As for pre- or post-departure testing, we need to remember that testing is no silver bullet. It’s a measure of viral load at a point in time and hasn’t stopped transmission of the virus on planes. It’s not even clear it would have picked up our Sydney visitor. Pre-departure testing 72 hours before certainly wouldn’t have. If we have the capacity, it may be a good idea to swab people on arrival if there are community cases in Australia but not enough to put a pause on the trans-Tasman bubble. Again, it wouldn’t guarantee people didn’t have the virus, but it would pick up anyone who was infectious but not yet symptomatic. 

The way it could have been avoided was if the trans-Tasman bubble had been paused earlier. It was paused on Tuesday June 22, a full week after the first case in Sydney. So why wasn’t it paused earlier? Until that Tuesday, almost all cases were linked to the original case which had a clear link to the border. It’s clear to me that health officials and the government here are trying to balance the risk of a case arriving in New Zealand with unnecessary disruptions to travel if the risk is very low. And the risk was very low. But it wasn’t zero. And this time it didn’t work in our favour.

And that is why we should never be complacent. Remember, the Swiss Cheese Model? Make it a habit to scan in everywhere you go. Wear a mask, especially indoors. Get tested if you have any symptoms that could be Covid-19. And get vaccinated when its your turn.    

Keep going!