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Image: Toby Morris
Image: Toby Morris

ScienceJanuary 24, 2022

Siouxsie Wiles: Omicron is in our community. Here’s how we can reduce the risk

Image: Toby Morris
Image: Toby Morris

Omicron is here and vigilance is key so here’s a reminder of what we can all do to lower risk.

With multiple cases of omicron identified in the community, New Zealand has moved to the red setting of its traffic light system which aims to slow the spread of Covid-19 using vaccination, masking, physical distancing, and limits on gathering sizes. The big question is, will these measures be enough? 

Over the last two years we’ve seen different countries take very different approaches to dealing with the pandemic. At one extreme we have those that continue to put minimal restrictions in place, preferring to let the virus infect as many people as possible. At the other extreme we have countries like China that continue to pursue an elimination strategy by stopping the virus at the border and stamping out any community outbreaks. 

Here in New Zealand, we started out with an elimination strategy and in late 2020 transitioned to something a little different. While continuing to try to stop the virus at our border, we moved to using vaccines and other public health measures in place of lockdowns to minimise the spread of Covid-19 in the community. This system worked well for the delta variant, but I’m worried it’s not going to be good enough for omicron. 

Omicron has changed the game, again.

Because of a lack of global agreement and support to try to minimise transmission of Covid-19 everywhere, the virus responsible for Covid-19 continues to evolve. With omicron, we now have a variant that is more infectious and better able to infect people who have been vaccinated or had a previous infection. These factors mean that case numbers around the world have been growing at an astonishing rate, in some places doubling every few days. 

All around the world, these rapid rises in omicron cases have been followed by rapid rises in hospitalisations and deaths. Despite what you might have heard, the SARS-CoV-2 virus isn’t evolving to be less deadly. As well as being more infectious than earlier variants, delta has resulted in hospitalisation rates that are twice that of earlier variants of the virus. Because omicron has arisen from a separate branch of the SARS-CoV-2 virus family tree, if you want to know whether omicron has evolved to be less dangerous, you need to compare it to the original version of the virus, not delta. Yes, some of the data is suggesting omicron isn’t quite as bad as delta, but it is still nasty enough. What makes Covid-19 in general appear less dangerous is the fact we now have a better understanding of how to care for seriously ill patients, coupled with effective antivirals and vaccines that are keeping a lot of people out of hospital and intensive care.   

While many people with omicron will recover at home, the reality is that the sheer number of people infected has brought healthcare systems around the world to their knees. In the UK, more children have been hospitalised by omicron over the last couple of months than were hospitalised by all the other variants going back to the start of the pandemic. Elective surgeries have had to be cancelled, and people are dying of heart attacks and other non-Covid related health issues because there aren’t enough ambulances or hospital beds. On top of that are problems with staffing as so many people have either been home sick or isolating after being exposed. That’s affected not just hospitals but lots of different workplaces, resulting in collapsed supply chains and empty supermarket shelves. 

And don’t even get me started on the potential long-term impacts of infection. So many people are suffering debilitating symptoms months after they have had Covid-19. Some of them only had a mild infection. In the last few weeks, researchers using data from millions of US military recruits monitored over 20 years reported that multiple sclerosis looks to be caused by infection with Epstein Barr Virus. What will we be finding out about Covid-19 over the next few years?   

We must minimise the transmission of omicron.

To reduce the impact of omicron on our health and economy, we need to do everything we can to reduce the spread of the virus. This is what living with Covid-19 should mean to us now. Remember our “break the chain” graphic? What are the actions that each of us can take every day to reduce the chances of either being exposed or spreading the virus if we are infectious and don’t know it? It’s these small actions every day that will make a difference to you and everyone around you. 

To help understand what actions are important and when, here are the crucial things to remember: 

  1. The virus spreads through the air
  2. Indoor spaces with poor ventilation are hot spots for transmission 
  3. People can be infectious before they know they are infected. 

Our traffic light system relies on isolation, vaccination, masks and distancing to reduce transmission. 

Isolating if you are exposed or infected is crucial.

Because people are infectious before they realise, it is important for people to isolate when they have been exposed and to get tested if they have any symptoms that could be Covid-19. Make sure you’ve got a plan for how to isolate should you need to. The government has signalled that at some point rapid antigen tests will be brought in to help with testing. Data from overseas is providing important information on using these kinds of tests when omicron is widespread. One important thing to remember is that these tests are not as sensitive as PCR tests so people can be infectious before they test positive.

There’s also lots of anecdotal stories of nasal swabs being less sensitive than throat/saliva swabs so people are often testing negative with a nasal swab but positive with a throat swab or saliva sample. Overseas data is also providing important information on the sensitivity of the PCR test with omicron. A recent study from South Africa found that testing saliva was better for omicron than testing nasal swabs. If we aren’t going to switch to testing saliva, then we can’t assume a negative test means someone is definitely negative.

Vaccines are important.

Recent studies have shown that three doses of the Pfizer vaccine provide really good protection against serious disease from omicron so please get boosted as soon as you are eligible. If you are a parent, please get your children vaccinated. Omicron has the potential to cause very serious disease and those who are unvaccinated are much more likely to be hospitalised.

Masks are a crucial defence against Covid-19.

Even if you are vaccinated, masks are a crucial defence against Covid-19, providing they fit well and cover your mouth and nose. It is no use wearing a mask under your nose so you can breathe more easily. If you are using a fabric mask, I’d be upgrading to one that includes a PM2.5 filter or wearing one over a surgical mask. FFP2, KN95, or KF94 masks are better options but beware of where you buy these from as there are many counterfeit masks on the market. Masks can be reused, so try to have one for each day of the week, and store in a paper bag between uses. Replace if they become wet or soiled, or the straps loosen so they don’t fit as well.


I wish there was less focus on distancing and more focus on the dangers of shared air. Unfortunately, distancing isn’t much use in small indoor environments, especially those with bad ventilation. I’m especially worried about indoor environments where people aren’t wearing masks. For these, we need to be improving ventilation and preferably using portable air purifiers that can remove the virus from the air. 

I know this is an unsettling time for everyone. I’ll leave you with mine and Toby’s list of the factors to consider to help minimise your chances of both catching and spreading Covid-19. I really hope we can keep cases low so that we don’t experience the devastation that people overseas have experienced and continue to experience.

Keep going!