What is COVID-19

Information about COVID-19 including where the virus came from, how it spreads, current variants of concern including Omicron, and treatments.

About COVID-19

COVID-19 is a disease caused by the coronavirus SARS-CoV-2. It affects your lungs, airways and other organs.

Coronaviruses are a large and diverse family of viruses that cause illnesses such as the common cold. Other recent diseases caused by coronaviruses include severe acute respiratory syndrome (SARS) and Middle East respiratory syndrome (MERS).

SARS-CoV-2 was first recognised in China and likely originated in animals. It is still unclear how the virus came to infect humans. The disease spread to other countries, with the World Health Organization (WHO) declaring a pandemic on 11 March 2020.

The virus has since undergone genetic mutations over time as it adapts to humans. Some of these mutations can spread more easily than the original virus.

Variants of COVID-19

It is a natural process for viruses to change or mutate, which may produce variants. Variants are developing around the world. This tends to happen in places where the virus is out of control.

WHO is tracking variants of concern and variants of interest.

Tracking SARS-CoV-2 variants | World Health Organization (external link)

Variants of COVID-19 may affect how fast the virus spreads, or how sick people get from the virus.

The Ministry of Health is providing updates on these variants and has a framework to prepare and respond to any new variants of concern.

COVID-19 variants | Ministry of Health (external link)

About the Omicron variant

Omicron was first classified as a variant of concern by WHO in November 2021. It has spread worldwide and is now the major variant in many countries. It is more transmissible than previous variants of the virus, including Delta.

How Omicron is different from earlier variants

Compared to Delta, Omicron:

  • is more transmissible
  • causes similar symptoms, but because we have a highly vaccinated population, many people may not have any symptoms (though could still pass the virus on to others)
  • has resulted in many more people being hospitalised than at any other time in the pandemic, because Omicron can cause many more infections over a short period of time
  • can still cause severe illness and even death, especially in people who are at high risk of severe outcomes, such as older people and people with underlying health conditions.

New variants

Omicron, like other variants, continues to change. New Omicron sub-variants BA.2.12.1, BA.4 and BA.5, which are circulating in New Zealand, are likely to replace BA.2 as the main sub-variants in New Zealand.

BA.2.75 has recently arrived in New Zealand. It is a second-generation subvariant of BA.2. Initial evidence suggests it may be slightly more transmissible, but assessing BA.2.75 is still at an early stage.

Although there continue to be new variants of Omicron, there does not appear to have been a change in the severity of the disease due to these variants. The public health settings already in place to manage current Omicron variants are appropriate for managing the subvariants present in our community.

Detecting variants

To identify which variant a person has, there needs to be whole-genome sequencing. This can happen through a polymerase chain reaction (PCR) test.

We have a system in place to identify any new variants arriving in New Zealand. People who arrive from overseas and test positive with a rapid antigen test (RAT) should have a follow-up PCR test to identify the variant they have.

How COVID-19 spreads

COVID-19 is spread from person to person. When an infected person breathes, speaks, coughs, sneezes or sings, they may spread particles containing the virus.

These particles range in size. Larger and heavier particles — droplets — quickly fall to the ground or other surfaces within seconds or minutes. Smaller particles — aerosols — can remain airborne for minutes to hours.

COVID-19 is mostly spread by aerosols, which is why air ventilation is important. Getting COVID-19 off a surface is less common, but it is still important to clean surfaces to reduce the risk.

The risk of airborne transmission becomes higher:

  • in enclosed spaces that do not have good airflow
  • in crowded places with many people nearby
  • in close-contact settings, such as close-range conversations, singing, or shouting.

The risk is lower outside, with fewer people, and if people are widely spread.

How to protect yourself and others

Keep up healthy habits

Keeping up healthy habits can slow the spread of the virus and help protect you, your whānau, and your community from COVID-19, including variants. Even if you are vaccinated, you still need to keep up these habits.

Healthy habits

Get vaccinated

Getting vaccinated means you are far less likely to get really sick and have to go to hospital if you catch COVID-19. You are also less likely to pass COVID-19 on to other people.

While a 2-dose course provides some protection against severe disease from Omicron, protection against infection can decrease over time. A booster will improve protection against Omicron by reducing the chance of more serious infection and the risk of transmitting it to others.

Get your vaccine booster

COVID-19 symptoms

The symptoms of COVID-19 are like common illnesses such as the cold or flu. Some people will only experience mild to moderate symptoms. Older people, ethnic minorities, and those with underlying medical conditions are at higher risk of severe illness from the virus.

Some people who have had the virus are suffering health impacts longer than a few weeks or months. This is commonly referred to as Long COVID.

Symptoms of COVID-19 and Long COVID

People at higher risk of COVID-19

COVID-19 treatments

There are medicines to treat COVID-19 available for people who are at risk of developing a serious illness.

When taken early on in your COVID-19 illness, they can help you get better faster and stay out of hospital.

Medicines to treat COVID-19

Our response to COVID-19

Aotearoa New Zealand’s strategy with the COVID-19 Protection Framework (also known as the traffic lights) is for New Zealanders to connect with friends and whānau, while also protecting everyone from serious illness.

We do this through:

  • testing anyone with symptoms
  • hygiene measures such as washing our hands and wearing a face mask
  • testing and tracing potential contacts
  • isolating cases and their contacts.

Traffic lights

New Zealand’s vaccine plan

High rates of vaccination is New Zealand’s key tool in protecting people and minimising the spread of COVID-19, and central to the settings in the framework. The COVID-19 vaccine is free and available to everyone in New Zealand aged 5 and over.

COVID-19 vaccines

Wastewater testing

Wastewater testing is being used as an extra tool to help monitor COVID-19 in New Zealand. It is being used as a surveillance tool alongside testing of symptomatic people in the community.

Wastewater testing for COVID-19 | Ministry of Health (external link)

The Institute of Environmental Science and Research (ESR) tests wastewater around the country. An interactive dashboard shares ESR’s wastewater science. It can help you track potential COVID-19 risk in your area.

COVID-19 wastewater testing results around the country | Institute of Environmental Science and Research (external link)

Last updated: at