The Swedish Public
Health Agency (Folkhalsomyndigheten) has developed national
criteria for assessing freedom from infection in
The PCR technology used in
tests to detect viruses cannot distinguish between viruses
capable of infecting cells and viruses that have been
neutralized by the immune system and therefore these tests
cannot be used to determine whether someone is contagious or
RNA from viruses can
often be detected for weeks (sometimes months) after the illness
but does not mean that you are still contagious.
There are also
several scientific studies that suggest that the infectivity of
Covid-19 is greatest at the beginning of the disease period.
The recommended criteria for assessing freedom from infection
are therefore based on stable clinical improvement with freedom
from fever for at least two days and that at least seven days
have passed since the onset of symptoms.
For those who have
had more pronounced symptoms, at least 14 days after the illness
and for the very sickest, individual assessment by the treating
The criteria have been developed in collaboration with
representatives of the specialty associations in infectious
disease medicine, clinical microbiology, hygiene and infection
These have most
recently been discussed in the group at a meeting on 19 April
2021 due to the new virus variants. The assessment was then that
no update was needed.
will be updated as new knowledge about Covid-19 infectivity is