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One of the new cases in Auckland worked at LSG Sky Chefs, which provides food and laundry services to airlines around the world. (Photo by Andreas Arnold/picture alliance via Getty Images)
One of the new cases in Auckland worked at LSG Sky Chefs, which provides food and laundry services to airlines around the world. (Photo by Andreas Arnold/picture alliance via Getty Images)

ScienceFebruary 15, 2021

Siouxsie Wiles: Your questions on the latest NZ Covid cases, answered

One of the new cases in Auckland worked at LSG Sky Chefs, which provides food and laundry services to airlines around the world. (Photo by Andreas Arnold/picture alliance via Getty Images)
One of the new cases in Auckland worked at LSG Sky Chefs, which provides food and laundry services to airlines around the world. (Photo by Andreas Arnold/picture alliance via Getty Images)

Three new community cases of Covid-19 and an unknown source have plunged Auckland into lockdown and the rest of the country into alert level two. Microbiologist Siouxsie Wiles tackles some of the critical questions we now face.

Could we be looking at a situation as worrying as last August in Auckland?

Yes. Like in August, it isn’t clear yet how the family have come into contact with the virus. Also worrying is that the family have the B.1.1.7 variant which was first identified in the UK last year and is one of the more infectious variants of the SARS-CoV-2 virus.

One of the infected family worked at a company that provided laundry services to airlines. How likely is it that this is the source?

It’s a possibility, as part of their job has apparently been handling laundry items from international flights. We haven’t been told what they handle, though, so whether they were exposed to, for example, bedding or pillows that could have been used by someone infectious.

Another possibility is that they have been exposed by contact with a person at their workplace who works airside and has been exposed to infectious aircrew or passengers transiting through New Zealand.

Yet another possibility is that the index case is someone who has been through our MIQ system but didn’t become infectious until afterwards and has passed on the infection without being detected. I would hope that anyone who had been through MIQ and developed symptoms afterwards would have got tested. If it were this scenario, then it could be that the person didn’t develop any symptoms, but its still not clear just how infectious people like this are.

Can Covid transmit via laundry?

There certainly aren’t any reports I can find, but we have to remember that most countries have so much community transmission that they aren’t able to identify how people become infected, so a lack of reports doesn’t mean it isn’t a possibility. There’s at least one manuscript (that doesn’t seem to have been peer-reviewed yet) that looked at the survival of the virus on different surfaces, including what they described as “cloth”. They found the half-life of the virus was between three and 20 hours depending on the temperature and the humidity. This was a lab study so wasn’t looking at naturally contaminated fabrics or transmission from them, but it does suggest that virus could be present on fabrics used by infectious people.

Shouldn’t Taranaki also be in level three?

At the moment it’s not thought the family were infectious while they were in Taranaki, which is why it’s only Auckland at level three. It’s still important, however, that anyone who was at any of the indoor places the family visited at the times provided on the Ministry of Health website isolate and make arrangements to get tested. Of course, if anyone in Taranaki have any symptoms that could be Covid-19 they should call Healthline and ask about getting a test.

What does the genome sequencing tell us?

So far it tells us that the family have the more infectious B.1.1.7 variant first identified in the UK, and that it doesn’t match the sequence of anyone who has tested positive in our managed isolation and quarantine system.

The team at ESR are checking the global database to see if it matches a sample deposited by another country and health officials are following up with airlines to try to find out whether it could match an international crew member or transiting passenger. If that means there isn’t already a mechanism which automatically alerts our health officials to any passengers or airline crew flying to or from or transiting through New Zealand who test positive for Covid-19, then this is something we need to fix.

How much more vicious is this UK strain?

I’m not sure about vicious, but it’s certainly more infectious. It’s becoming the dominant variant in Britain. It’s now also been found in lots of other countries overseas so may start to become dominant there, unless they already have variants with similar mutations that are more infectious. There have been some reports from the UK that the B.1.1.7 variant has resulted in more hospitalisations and perhaps more deaths, but it’s hard to disentangle that from an increasingly overwhelmed health system.

Will the vaccine be effective against all these new strains?

That’s not fully clear at the moment. B.1.1.7 does seem to be slightly less well neutralised by antibodies from people exposed to older versions of the virus. There may be other versions that this is more of a problem for. It’s a watch-and-see situation for the moment. We’ll certainly get a better idea from those countries that are doing mass vaccination of their populations but not doing much else to stop community transmission or importation of new virus variants into their country.

Shouldn’t we have daily saliva testing for those at the border?

This certainly seems like a good idea though I’m not sure what the logistics of this are given just how many people work at the border. It may well be quite a big undertaking for an already very stretched health work force.

Some countries now recommend ‘double masking’. Should we be doing the same?

This is a recommendation for those countries with widespread community transmission where your chances of being infectious or encountering someone infectious are very high. It certainly wouldn’t hurt us to double mask, so consider doing it when you’re out in public, especially indoors.

Keep going!
Image: getty
Image: getty

ScienceFebruary 9, 2021

The house that climate built

Image: getty
Image: getty

Achieving our emission reduction obligations means changing the nature of our homes. Here’s how we can do that.

New Zealand’s homes need a refresh. Mouldy, leaky, cold homes that leach any semblance of heat to the outside world won’t cut it any more – if they ever did.

Aside from the health benefits, making homes more energy efficient cuts greenhouse gas emissions. Reducing Aotearoa’s emissions is front of mind after the Climate Change Commission released its advice last week.

The commission recommends the country should cut emissions from buildings, both residential and commercial, by roughly 28% by 2035 to meet its greenhouse gas reduction targets.

The commission’s roadmap is a little light on advice on how to do that in terms of the actual physical, built structure. Instead it emphasises the need to move away from heating homes with coal and natural gas.

But there’s a skyscraper-full of ways to make homes less bad for the planet, and ourselves. This is a rundown of some of those options, ranging from the obvious and easy to the downright weird.

Get real windows and insulation

Every view to the outside world is essentially a hole that precious heat seeps from. Make those holes better at reducing heat loss, or heat gain, and you’ve got yourself energy and emissions savings.

One study estimates that you can reduce energy consumption by as much as a third in existing buildings by glazing windows, adding insulation, plugging up gaps in ceilings and putting in awnings, blinds or trees on the sunny side of the house.

Another estimates glazing and shading reduces a building’s carbon emissions by 2.1% every year.

The extreme end of this is a passive house — one that’s super insulated, faces to capture the sun and is air-tight. A passive home could reduce emissions by 30% over its entire life (from sourcing materials, to transport, to final house) compared to a regular dwelling.

Pick materials wisely

Different building materials take a different amount of energy to make therefore affecting the amount of greenhouse gases they let off before they even become part of a house.

For example steel is made through an energy-intensive process that’s pretty much remained unchanged since the 14th century. Timber on the other hand is fairly cheap emissions wise to source and could actually store carbon. Keeping steel to an only-where-needed material and maximising wood use is one of the suggestions the commission makes.

The perfect combination of materials, according to a study from Singapore and China, is porous brick for the walls, windows made from low heat-emmitting glass with plastic frame, a flat roof, a raised floor with natural ventilation, wool or glass cotton insulation, and lots of shade.

Or you could go fully eco and use recycled materials, like the University of Brighton’s Waste House. It uses VHS tapes, DVDs and old denim as insulation, recycled wood as walls and bike inner tubes for sealing windows. No extra production energy needed.

Build up and a little out 

Since the country is in dire need of a few new builds, it’d be wise to consider what shape those take and how that affects emissions. Tall high-rises can fit more people per bit of land and might be able to trap heat better, but they also need more steel for support and extra structures like elevators.

A 2015 study weighed up these various factors and concluded that a four-story building with a centre courtyard had the lowest carbon footprint out of options including a 215, 58 or 16 story high-rise, smaller urban home or larger suburban home.

More people per area of land could also mean less distance between home and work, which would make taking a bike or walking to work easier, meaning more emissions savings.

IKEA-fy houses

The beauty of flatpack furniture isn’t the hours you spend figuring out how to put it together but its emissions savings. Pieces can be cut from materials in a way to minimise waste and, because it packs flat, more boxes of shelves or what have you can fit onto the same transport truck or plane, lowering the emissions per item.

Same idea goes for houses. Instead of lugging a bunch of two-by-fours to the building site and leaving offcuts behind, flatpack houses are partially preconstructed and then assembled on site.

One study compared the total greenhouse gas emissions for building a house the ol’ fashioned way on site and IKEA-style. They found that the flatpack method could be 30% more efficient.

Even if they’re not totally flatpack, just being savvy about not using more building material than is necessary could save around 18% in emissions, according to a UK report.

Cob-and-home

Cob houses are made from a natural building material, a mix of straw, sandy soil and a bit of gravel. Materials are usually sourced on-site (no or low transport emissions) and those materials have a low carbon footprint.

A cob house could generate around 30% fewer greenhouse gases over its life than a regular concrete house. Most of those savings came from the materials used, even though a cob house needs more of them.

The New Zealand version is whare uku, which uses harakeke instead of straw and has the added benefit of being low cost to build (around $150,000).

Dome sweet dome

Forget about hanging a picture on the wall but dome houses are a potentially carbon neutral housing alternative.

They look like little greenhouses but are made from ceramic tiles which can absorb carbon from the environment. Although the company that’s planning to make them doesn’t promise anything, they think that the ceramic plates could end up absorbing more carbon that it took to manufacture the house.

But their shape is their true selling point when it comes to cutting carbon. The domed roof maximises surface area, while keeping the same floor area. That means the domes naturally have double the insulation properties of a regular house with the same floorprint.

And when you’re done, just pop the tiles into an “emerging vortex wind technology” device or “tornado in a can” to pulverise them to remould into new panels or use as fertiliser.

Plus they look like cities of the future.

But wait there's more!