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.
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).