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COVID-19 (coronavirus disease 2019) is a respiratory viral infection caused by SARS-CoV-2 virus. From late 2019, this disease rapidly spread resulting in a pandemic. Early symptoms of COVID-19 include a dry cough, sore throat, fever, loss of taste and smell, tiredness, gastrointestinal symptoms, such as diarrhoea and pain, and muscle aches. In some people, particularly in older people and those with chronic health issues, it develops into pneumonia and widespread inflammation requiring hospitalisation and ventilation support in intensive care.


COVID-19 is a respiratory infection caused by a coronavirus called SARS-CoV-2. It initially affects your upper airways and can move to lungs. This virus was first identified in China in 2019 prior to which it had not previously been seen in humans or animals. Coronaviruses are known to cause mild illnesses like common colds but also other severe diseases like severe acute respiratory syndrome (SARS), Middle-East respiratory syndrome (MERS).

How you catch it

SARS-CoV-2 virus is primarily spread person to person by aerosols of droplets from airways, such as through coughing and sneezing. Being in a poorly ventilated space, in close proximity of someone who is infected and being exposed for several minutes increases the risk of being infected. Singing and loud conversation can increase spread from infected people. As new variants of the virus spread, they have become increasingly more infectiousness and more transmissible.

Health care workers exposed to patients with high viral loads are at increased risk of severe COVID-19 disease if not adequately protected by personal protective equipment and vaccinated.


The early symptoms of COVID-19 appear like other respiratory viral infections, with fever, dry cough, tiredness and muscle aches. Other symptoms include a sore throat, chills, nasal congestion, headache, nausea and diarrhoea. An unusual but common symptom is the loss of taste and smell that is not associated with nasal congestion. For some people, this disease becomes much more severe, causing pneumonia and breathing difficulties. This can lead to acute respiratory and organ failure and wide-spread inflammation, which require hospitalisation and intensive care.

Symptoms appear after infection following an incubation period of 2 to 5 days (up to around 14 days) and the virus can be spread for 1 to 2 days prior to any symptoms and peak at around 3-5 days after symptom onset. Those with symptoms have the most virus and are more likely to spread the infection. However, spread can also occur from those who are incubating the virus (presymptomatic) or those who remain asymptomatic (with no symptoms) but this is less common.  Vaccination helps to reduce the time of infectiousness and likelihood of developing symptoms.


Apart from supportive medical care, there are few treatments for COVID-19. Two antiviral medications are available and funded to support certain older or high risk individuals with COVID-19 infection to reduce the risk of severe disease: nirmatrelvir with ritonavir (Paxlovid) and molnupiravir (Lagevrio). For more information about these medications see Ministry of Health webpage COVID-19 medicines


The effects of COVID-19 can range from mild to severe:

  • COVID-19 can be fatal (over 2.5 million people died in one year globally, and numbers have continued to increase).
  • The risk of severe COVID-19 and death increases with age and in those with chronic health conditions, such as diabetes, obesity and chronic respiratory disease, and including pregnancy.
  • Long-lasting effects of COVID-19 have been observed, even in those who have had relatively mild symptoms.
  • Preterm birth is a risk for the infants of women who have COVID-19 when pregnant, particularly due to emergency delivery in mothers with breathing difficulties.


  • As part of the initial pandemic response between March 2020 and mid 2022, the New Zealand Government implemented public health control measures to slow the spread of SARS-CoV-2 to prevent COVID-19 disease. See Unite Against COVID-19 for further details.
  • Testing for the virus, rapid contact tracing and border restrictions were put in place to detect and limit community transmission
  • Good hand-washing hygiene, social distancing, masking wearing and staying home when unwell help to reduce transmission.
  • Immunisation with COVID-19 vaccines commenced in 2021. See COVID-19 vaccines in NZ.
Coronavirus disease 2019 (COVID-19)
Complications of disease
  • Pneumonia
  • Acute kidney and liver injury
  • Neurological – brain inflammation, haemorrhage, seizures
  • Cardiovascular – inflammation of the heart (myocarditis), stroke, heart failure
  • Venous thrombosis – blood clots
  • Acute respiratory failure
  • Multisystem inflammation
  • Post-intensive care syndrome – reduced muscle and brain function
  • Long-COVID syndrome – fatigue, depression, memory loss, cough
  • Death
Responses to vaccine

Common responses

  • Pain at injection site
  • Headache
  • Fatigue
  • Muscle aches
  • Chills
  • Fever
  • Joint aches
  • Nausea

Rare responses

  • Lymphadenopathy (swollen lymph nodes)
  • Myocarditis or pericarditis (inflammation of heart)

As with any medicine, very rarely, severe allergic reactions can occur following immunisation.

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