As of midnight, the borders with Norway have been closed after a spread of the mutated British virus was discovered in the Oslo area.
The mutated virus also occurs in Sweden, but not to any great extent.
Occasional cases have appeared in many regions, and now a case has been discovered in Jönköping County.
- I can not say anything about the individual, other than that he was infected in the UK.
Infection tracking has been carried out and no more cases have been identified, says Malin Begnér who is an infection control doctor in the Jönköping County Region.
It is unclear how serious the virus is
Malin Begnér says that she is not particularly surprised that the new mutation has now appeared in the county, but that it is important that the new mutations are closely monitored all over the world so that we learn more.
- We still have limited knowledge about what the altered gene sequence means for infectivity, disease picture, immunity and more, so it is difficult to say how serious this particular mutation is.
It is natural that viruses change all the time, all viruses do, she says.
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"People are frightened by the various mutations," says Tomas Bergström, who is a professor of clinical microbiology.
Photo: SVT