Incubation time and transmission

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 if your hands come into contact with the virus and you then touch your face.

What you can do to prevent infection

  • Avoid coughing or sneezing directly onto others.
  • Keep a distance of minimum one meter to people who cough.
  • Cough / sneeze into a paper tissue that you carefully dispose, and then you have to wash your hands.
  • If you do not have tissues at hand, cough into the crook of your elbow to avoid spreading airborne virus via droplets.
  • Wash hands frequently and thoroughly with soap and lukewarm water, particularly when you have been in contact with other people.
  • If hand washing is unavailable, you can resort to hand disinfection products that contain alcohols. Note that hand disinfection has a limited effect if your hands are visibly dirty or wet.
  • Find alternatives to shaking hands, kissing and hugging.

Incubation time and symptoms

The incubation time is the time from transmission until symptoms appear. World Health Organization (WHO) has estimated the incubation time for the coronavirus to be 5-6 days, but this can vary from 0 to 14 days.

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 feeling generally unwell and having muscle pain. Diarrhoea may occur but is not common.

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 there are 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 about risk factors for severe disease is currently limited. Admission to hospital, intensive care treatment and death are more common among the elderly and people with underlying diseases. Particularly elderly people with underlying diseases are at risk, but severe illness can also occur among people without known risk factors.

There is no specific treatment or vaccine for the disease, but hospitals in Norway have 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).

Clinical trials for COVID-19 (in Norwegian):

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 that can be seen with coronavirus.

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 prior to symptoms developing.
  • If you are ill, stay at home.

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.

WHO has declared a pandemic, what does this mean?

A pandemic can be defined as "a disease outbreak that afflicts a very large amount of people and spreads beyond expectations across large parts of the world".

Thorough handwashing is important to prevent contact transmission

Hand hygiene is an effective measure to prevent disease.

  • People who are ill should wash their hands carefully when there is a risk of infectious material on their hands (e.g after blowing your nose), before they touch any objects.
  • Washing hands with soap and lukewarm water is recommended. Hand disinfection products are a good alternative if hand washing is unavailable and can also be carried out by the sickbed.
  • It is also important that family members and others who are in contact with people who are ill are extra attentive to their hand hygiene. This goes both for contact with the person who is ill, and with objects that can contain infectious material such as paper tissue.

Who should be tested for the coronavirus?

Those who are in home isolation will not be tested and should not contact the healthcare services unless they are in need of medical attention.

Testing is reserved for certain groups of patients and health professionals who develop respiratory symptoms.

Testing criteria are assessed continuously.

Cleaning in households and in public

It is uncertain how long the coronavirus can survive on surfaces. This will vary under different conditions, such as type of surface, temperature, sunlight and air humidity. As virus can be found on surfaces, handwash is the key preventive action.

The Norwegian Directorate of Health encourages all companies who provide public transport to initiate extraordinary cleaning of subway trains, buses, trams etc. The Norwegian Directorate of Health also encourages extra cleaning in areas where high numbers of people frequent.