COVID-19: About the Omicron variant

Omicron was first identified in mid-November 2021. The World Health Organization rapidly classified Omicron as a variant of concern due to the large number of mutations it contains, with at least 30 located in the spike protein.

Last updated: 25 March 2022

The Omicron variant has spread worldwide rapidly and is now the major variant in many countries. Omicron is much more transmissible than previous variants of the COVID-19 virus, including Delta. Omicron, like other variants, continues to change and there are now two main sub-variants – BA.1 and BA.2. The BA.2 subvariant is more dominant in New Zealand but both BA.1 and BA.2 are circulating.

The BA.2 sub-variant is also more infectious than the BA.1 sub-variant and is contributing to the increase in the number of cases in many countries around the world. BA.2 is not more severe than BA.1 and is not leading to more hospitalisations, but it is possible to be infected by BA.2 after recovering from BA.1.

The rapid emergence of Omicron has required yet another change in the way New Zealand manages COVID-19. The large increase in the ability of Omicron to spread in the community has changed the public health rationale from when the risk assessments and Vaccination Assessment Tool were introduced.

How Omicron is different from earlier variants

Although Omicron is a new variant, there is already much that we have learned about it.. Most of this information has come from overseas, where Omicron started earlier, but it is important to understand that all countries are different, so the information needs to be carefully analysed to see how it will apply to New Zealand and particularly to Māori and Pacific peoples.

New Zealand has a very effective system in place for identifying new variants by performing whole genome sequencing. The ongoing emergence of new variants such as Omicron underline why it is so important that we continue to perform whole genome sequencing on cases from overseas where possible and those not linked to a cluster in New Zealand.

What we know about Omicron and vaccination (in this case with the Pfizer vaccine)

  • a person is significantly less likely to be severely sick, hospitalised or die from Omicron if vaccinated, especially following the third (booster) dose
  • Real life evidence highlights in those countries with high vaccination rates (~95%) that this does provide some population immunity on top of individual immunity
  • While vaccination provides less protection against contracting and transmitting the Omicron variant compared with earlier variants, it still provides some protection, especially after the third (booster) dose.  

Health advice, based on the evidence we have, is that the Omicron variant can still be contracted and transmitted by vaccinated people. Other key public health measures should continue to be deployed to reduce the spread of the virus. These include:

  • Vaccination (increasing booster rates to the highest possible level)
  • Staying home when sick
  • Mask use in indoor settings
  • Improving ventilation
  • Physical distancing
  • Basic hygiene practices.

High rates of vaccination remain critical to prevent severe disease and death, especially in vulnerable people. In addition, it affords some individual protection against infection and transmission of the virus and broad population protection with high vaccination uptake.

In addition, there is still the potential for new variants of the virus that are both more transmissible and more virulent and vaccination (with the current Pfizer or another vaccine that proves to be more effective against a new variant), will continue to play a central role in reducing the risk of transmission and of severe illness and death as the pandemic continues to evolve.

What New Zealanders can do now:

  • if you are eligible to have your COVID-19 vaccine booster shot, please make a booking here. 5–11 year olds are also now able to receive the pediatric Pfizer vaccine
  • prepare a kit for your home and make a plan if you or someone in your household becomes a positive COVID-19 case. Prepare and stay safe
  • continue to follow good hygiene practices and wear masks
  • if travelling around the country over summer, have a plan in place if you become unwell or test positive. See advice here.


  • Omicron is more transmissible than the Delta variant
  • Whilst still causing illness, a person is less likely to be severely ill if they contract Omicron than Delta
  • Omicron is currently circulating at high rates throughout New Zealand.


  • Omicron probably causes similar symptoms to other variants, such as Delta. However, in a country that has most people vaccinated, many people may not have any symptoms at all, but still be able to pass on the virus to other people.

See COVID-19 symptoms for more information.


  • Omicron has resulted in many more people being hospitalised than at any other time in the pandemic. Thisis not because Omicron is very severe but because Omicron can cause so many infections over a short period of time.
  • Omicron can still cause severe illness and even death, especially in people who are at risk of severe outcomes, such as elderly and those with severe underlying health conditions. However,  a smaller proportion of people who are infected with Omicron need to go to hospital compared to people infected with Delta.

Please also see the latest information about Omicron in our Variants Update on the COVID-19: Science news page.

How we can protect ourselves: vaccine effectiveness and health measures

Vaccination and boosters help to reduce transmission of the virus. Remember, that if you don’t get the virus, you can’t give it to someone else. Taking other precautions also remains important to continue to protect our communities against Omicron. As well as vaccination, early detection of cases and swift contact tracing, and isolation of cases and contacts, is critical.

It will also be important to continue to protect ourselves and our whānau and stop the transmission of the disease by following health habits such as:

  • Keep indoor rooms well ventilated (eg, by opening windows and doors) where possible
  • Wearing masks and face coverings is one way of keeping yourself safe and protecting others from COVID-19, especially when physical distancing is not possible. Wear masks in confined or crowded environments.
  • Physical distancing of 2m where possible
  • If you feel unwell or show any symptoms, stay home. Call Healthline and get a COVID-19 test
  • Use your My Vaccine Pass to scan into venues and events as required. MVP is a record of your COVID vaccination status
  • Turn Bluetooth on your phone in the COVID Tracer app so you can be contacted if you have been near a case.
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