Siouxsie Wiles

Dr Siouxsie Wiles is a research scientist with a background in medical and environmental microbiology. She has made a career out of combining her twin passions of bioluminescence (the production of light by living organisms — think glow worms and fireflies) and nasty microbes. In a nutshell, Siouxsie and her team make nasty bacteria glow in the dark to better understand infectious diseases. Originally from the UK, Siouxsie now leads the Bioluminescent Superbugs Lab at the University of Auckland. She was the 2013 winner of the Prime Minister's Science Media Communicator's Prize. Siouxsie is on Twitter @SiouxsieW

Why I’m confident there is no community transmission in NZ - Infectious Thoughts

Jun 25, 2020

Both the leader of the opposition Todd Muller and University of Auckland Professor Des Gorman have gone on the record as saying they suspect Covid-19 is spreading in the community in New Zealand once again. Let me explain why I don’t agree with them. As best I can tell there are two reasons Muller and Gorman have jumped to the conclusion they have. The first is that we’ve been told that more than 2,000 people may have left their 14 days of managed isolation between June 9 and 16 without being tested for Covid-19 as they should have been. The second is that over that same period more than 50 people left managed isolation before their 14 days were up on a compassionate exemption. Again, mostly without being first tested. Before I get into the nitty-gritty, it’s worth noting that … Read More

Why are we seeing these new cases of Covid-19 in New Zealand? - Infectious Thoughts

Jun 23, 2020

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. Read More

Simple rules to play it safe at alert level two - Infectious Thoughts

May 14, 2020

Today Aotearoa New Zealand wakes up in alert level two. It’s no secret that I would have preferred for us to stay at level three for another week or so. That’s because I’m worried we don’t quite yet know how effective level three has been at keeping us on our path to eliminate Covid-19. But the government has had the unenviable task of balancing this risk with keeping the “team of five million” together. This has become especially important as protests against lockdowns and restrictions ripple troublingly around the world. So what are the risks at level two and how can we “play it safe”? Just how many hidden transmission chains might there be in New Zealand? Let’s start with the thing I’m worried about – the potential for unknown cases or chains of transmission to still be out … Read More

Why getting tested quickly matters so much - Infectious Thoughts

Apr 30, 2020

For days now, the numbers of new confirmed and probable cases of Covid-19 in Aotearoa New Zealand have been in single figures. But they haven’t been zero. Lots of people have noticed and have started asking me why, after all the weeks we’ve spent in lockdown, we still have people testing positive for the virus. It’s a good question and I can think of several reasons. But before I get into that, a quick reminder. Here in New Zealand, we test for the genetic material of the virus. The test is very sensitive and reliable. It can detect very small amounts of the virus, and it can detect both viable infectious virus as well as bits of broken-down virus that are no longer infectious. When someone has symptoms and tests positive for the virus, that likely means they picked … Read More

Magic numbers and the mystery of Covid-19 silent spread - Infectious Thoughts

Apr 29, 2020

A few days ago it was reported that “2.7 million New Yorkers have already had coronavirus”. To put that 2.7 million in context, the Johns Hopkins University Covid-19 tracker records, as I write, 291,996 confirmed cases in New York, with 57,103 people in hospital, and 17,515 people having died. If the 2.7 million figure is right, that would mean most people with Covid-19 are not being tested or don’t know they’ve had the virus. I saw lots of smart people musing on social media about what this could mean for how many people in Aotearoa New Zealand might have had the virus already. Before I get into the data behind the 2.7 million, let me start with what those reports might mean for us here in New Zealand. Ready? Nothing. Nada. Zilch. Read More

Welcome to alert level three. Now let’s finish what we started - Infectious Thoughts

Apr 28, 2020

We wake today at alert level three. We are here because of the incredible job everyone has done while we have been in lockdown at alert level four. No one doubts how hard this has been for so many people. For their mental and physical wellbeing. For their livelihoods. This global pandemic has turned our world upside down. To everyone who has stayed in their bubble, cutting off physical contact with so many family, friends, and neighbours – thank you. To all the essential workers who had to leave their bubble so the rest of us could stay in ours – thank you. Because of you all, we have stopped Covid-19 from spreading like wildfire through our communities. By acting as we have, we broke the chains of transmission and likely saved thousands and thousands of lives. We should all … Read More

What do we mean we talk about the ‘elimination’ of Covid-19? - Infectious Thoughts

Apr 24, 2020

New Zealand is pursuing an ‘elimination’ strategy to counter the coronavirus pandemic. But that word, as with many terms in science, is not necessarily the same as its common usage. Here in Aotearoa New Zealand, our plan is to eliminate Covid-19. We have long since abandoned the “flatten the curve” strategy, which aims to slow the spread of the disease to the extent that it doesn’t overwhelm our health service, for something more ambitious. We want to eliminate it. But what do we mean by “eliminate”, exactly? Sometimes words we know well mean something else to other people. And that can lead to all sorts of confusion and misunderstandings. Eliminate is one of those words. When epidemiologists use the word eliminate in the context of Covid-19, they mean to bring the disease under control and reduce cases to zero … Read More

Just how widespread is Covid-19 in people with no symptoms? - Infectious Thoughts

Apr 22, 2020

Did you hear about the testing of the general population in Iceland for Covid-19 that found that half of the people who tested positive didn’t have any symptoms? When I heard that, the first thing I thought was: shit, there are heaps of people walking around spreading Covid-19! And they don’t even know it, aaargh! I had a similar thought when I heard that the entire 4,800 crew on the US aircraft carrier Theodore Roosevelt had been tested and 60% of those that were positive didn’t have symptoms. I wasn’t alone. I did a quick poll on Twitter and almost a third of the 4,721 people who voted thought there were thousands of asymptomatic crew members. More than half picked the right answer, though, which is that there wasn’t enough information provided to say anything about how many crew … Read More

About those cries of ‘over-reaction’ on NZ’s Covid-19 response - Infectious Thoughts

Apr 15, 2020

A group of six New Zealand academics yesterday announced their “vision for a balanced response” to the Covid-19 pandemic. They are calling that vision “Plan B”. They even have a website and a PR firm attached. They are clearly serious. Their plan is for New Zealand to return “to normality as soon as possible” by moving to something like alert level two. They want most people to be able to get back to work, for schools and universities to open, and for people to be able to travel around the country again. And the reason they are advocating this plan? Because, they say, “international health data and experience is showing that New Zealand’s lockdown may now be unnecessary, and even more harmful than the problem we’re trying to solve.” That’s … Read More

Should we all be wearing face masks to prevent Covid-19 spread? - Infectious Thoughts

Apr 06, 2020

Maybe you’ve seen the graph that says those countries where everyone wears a mask are the ones that have managed to keep Covid-19 under control? The first thing to say about that claim is that those countries also did lots of other things, too – they acted fast, with intense testing, contact tracing and quarantine. The reality is, when it comes to wearing a face mask there are pros and cons that differ depending on where in the world you are. I’ll get to these shortly. But this is a complicated one. Even the experts can’t agree on whether everyone should be wearing one. That’s raised accusations of racism as well as given life to several conspiracy theories. Face masks have become such a heated topic over the last few weeks that I’ve personally been harassed and threatened over … Read More