Alert level four is go. Let’s talk bubbles. Siouxsie Wiles explains what it’s all about, with illustrations by Toby Morris.

Read Toby Morris’s new Side Eye comic, created with Siouxsie Wiles, here. And more of Siouxsie’s writing here.

On Saturday March 21, Jacinda Ardern announced a four-level alert system for responding to the Covid-19 pandemic in New Zealand. She placed us at level two.

Two days later, with news that we very likely now had two cases of community transmission of the virus here, we were moved to level three. We were also told that we had 48 hours to prepare for level four – complete lockdown of everything but essential services for the entire country.

That kicked in at a minute before midnight. Here’s how it works, and why it is so important we all play our part.

Stopping the virus in its tracks

There are some things to know about Covid-19 to understand why the lockdown is so important. The way I’ve explained this before is to imagine that everyone could be part of an ever-expanding coronavirus transmission chain.

Because people can spread the virus for a few days before they have any symptoms, each person who contracts the virus can unwittingly pass it on to several of their whānau, friends and colleagues. Then each one of them can unwittingly pass it on to several of their whānau, friends and colleagues. This means that if, left unchecked, the number of cases grows exponentially. This is what we are seeing in so many countries overseas. Spinoff cartoonist Toby Morris’s illustration of that concept has circled the globe in recent days.

The way to stop the virus in its tracks is to stop this exponential spread. And that means breaking the chains of transmission. That’s the purpose of isolating people with the virus and identifying all the people they have been in contact with and who may potentially be infected – what is referred to as contact tracing.

Now that we had some cases of Covid-19 where we don’t know how people became infected, the best way to break any transmission chains is for us all to stay away from other people. Hence the lockdown.

The prime minister has suggested we think of ourselves as being in a little bubble with the people we live with. Our job for the next few weeks is to stay in our bubble. If it turns out someone in our bubble is incubating Covid-19, then the virus will be limited to our bubble. It won’t be able to spread any further. It also means if no one in our bubble has the virus then as long as we stay in our bubble, we will stay safe and save lives.

So, what makes a bubble?

For the vast majority of us, it will just be the people we are living with. For people with shared custody of children, the bubble will cover the houses the children move between. If a blended family covers three or more households, that ends up being a pretty big bubble, so please think about whether it is best for some of the children not to move between their families. This will be difficult, but the aim is to keep the bubbles small and stop the spread of the virus.

If older relatives are able to safely live on their own, then they should stay as their own bubble. If you live alone, and you have a nearby friend who lives alone, then the two of you can form a bubble and move between your two homes. If you have flatmates and your partner has flatmates, you can’t form a bubble unless one of you moves in with the other.

Stay at home

I’ve been getting lots of questions about we can and can’t do while we are at level four. Today the prime minister was really clear on this. Her advice: Act like you have Covid-19. Minimise the time you spend outside your home. That means no going for a leisurely drive or driving to the beach. What if you had an accident or your car broke down? There won’t be a coastguard to get us out of a pickle, so no boating or surfing.

You can go for a walk or a bike ride around your neighbourhood to get some exercise. You can go out to get essentials like food. But stay away from other people. No stopping to chat – even if you are two metres away from each other. Just give a wave and keep moving. Because the virus can live on surfaces for up to three days, don’t take your kids to the playground. Stay at home.

Remember, while we are physically distancing ourselves from everyone outside our bubble for the next few weeks, it’s important we stay socially connected. So be sure to schedule some online coffee mornings or dinner parties.

For the next few weeks, our essential workers will have to be outside their bubbles keeping things going so we can stay in ours. That means during this lockdown we have one really important job to do. And that is to save lives. And we do that by making sure we don’t burst any bubbles.