Symptoms, incubation time and course of the disease

Foto: Helsedirektoratet/Eline Korsnes Sundal

The coronavirus spreads mainly by droplet transmission. The virus is found in small droplets in the mouth and nose of an infected person and become airborne through sneezing or coughing. The airborne virus is then typically inhaled by people nearby. Contact transmission can occur when your hands come into contact with the virus and you then touch your face.

Symptoms of coronavirus infection

Symptoms resemble those with colds and influenza.

  • Fever, a sore throat and coughing.
  • Some people develop breathing difficulties and pneumonia.

People who become ill typically experience initial upper respiratory tract symptoms (sore throat, cold symptoms, mild cough), as well as a general feeling of being unwell and having muscle pain. Diarrhoea may occur but is not common.

The difference between symptoms of coronavirus and pollen allergy

During the months of spring, many people in Norway are affected by pollen allergy. The symptoms can resemble those of a coronavirus infection, such as a runny nose, sneezing, runny or itchy eyes and some also experience asthmatic distress.

However, pollen allergy does not bring about symptoms such as a sore throat, body aches or fever as can be seen with coronavirus.

Read more about pollen allergy and symptoms (in Norwegian)

Close contact

You are considered a close contact if you have been near someone who then shows symptoms of covid-19 within 48 hours, and you were 2 metres or closer to them for 15 minutes or more. You are also considered a close contact if you have been in direct contact (e.g hugging or shaking hands) or been in contact with secretes such as saliva, sweat, snot, mucus and tears from someone who is ill.

Transmission and incubation time

With more acquired knowledge about covid-19, the data now clearly indicates that transmission most often occurs just when you turn ill and at the beginning of the course of the disease.

There are clear indications that the risk of transmission is relatively high one to two days before the onset of symptoms. On this basis, both the World Health Organization (WHO), the European Centre for Disease Prevention and Control (ECDC) and the Norwegian health authorities now recommend that contact tracing is done from 48 hours prior to the onset of symptoms.

Incubation time

The available information about incubation time is becoming increasingly clear. There is a clear trend in studies that very few people turn ill more than 8-9 days after being exposed to the virus. Quarantine time is therefore now set at 10 days.

Exempt from quarantine after covid-19

Persons who have had covid-19 are predominantly likely to be protected against a recurrence of the disease, but it is not yet known for how long this protection will last. It has therefore been decided that those who have had a confirmed (laboratory tested) covid-19 infection within the last six months are exempted from quarantine.
Anyone showing symptoms of an acute respiratory infection shall – like everyone – stay at home for an additional 24 hours after being free of symptoms.

End of isolation

You should be completely free of symptoms in order to end the isolation. You need to be free of symptoms for 72 hours with a period of at least eight days having passed since the first symptoms appeared. For persons in hospital or who undergo immunosuppressant treatment the requirement for insulation may be longer.

The Norwegian Institute of Public Health provides advice on isolation and how long you should be in isolation (in Norwegian).

The Norwegian Institute of Public Health's reasoning for adjusting the quarantine rules from May 7th 2020 (in Norwegian).

What should I do if I suspect that I am infected?

  • If you feel unwell, you should stay at home.
  • If you are ill and need medical attention or individual health counselling, contact your doctor electronically or by telephone.
  • If you need urgent health assistance and cannot reach your doctor, you can call the emergency out-of-hours clinic (116 117).
  • Call 113 only when life is in danger.


Can the virus be transmitted by people who do not display any symptoms?

While the most typical route of transmission is via a person who displays symptoms, infection can also occur just prior to symptoms developing.

Who should be tested for the coronavirus?

The Norwegian Institute of Public Health has developed a list of who should be tested, per order of priority, and in line with the situation, development and capacity of testing in Norway.

If you have an acute respiratory infection, fever, coughing or breathing difficulties, testing for covid-19 is recommended by the Norwegian Institute of Public Health assuming order of priority order at limited capacity.

Contact your doctor or visit the homepage of your municipality for further information on where to be tested, if relevant.

Criteria for testing are assessed and updated continuously. (

The course of the disease

The course of the disease can vary widely between individuals. Currently, the typical courses appear to be:

  • Mild course (this applies to the majority of those who become ill, about eight out of ten): Symptoms pass within one to two weeks and these is rarely a need for treatment from the healthcare service.
  • Moderate course: After 4-7 days of mild symptoms, some people may experience breathing difficulties, worsening cough and a rising fever. If you experience breathing difficulties, you should contact your doctor. Some will need to be admitted to hospital.
  • Severe course: As for the moderate course, but these people also need intensive care treatment. They may have symptoms for 3-6 weeks. Some of those who become severely ill will die from the disease.

Information and knowledge about risk factors for a severe progression of covid-19 is constantly growing. Admission to hospital, intensive care treatment and death are more common among the elderly and people with underlying diseases. The risk is in particular increased with age and underlying diseases. Younger persons without any known risk factors, can also experience a severe illness, but the risk is higher with underlying disease.

Treatment of coronavirus disease

There is no specific treatment or vaccine for the disease, but hospitals in Norway have now started registering patients with confirmed coronavirus infection in the Norwegian pandemic register (Norsk pandemiregister) to allow for improvements in treatment and follow-up.

You can find more information about the Norwegian pandemic register here (in Norwegian).