According to the Swedish Public Health Agency's recommendations, at least four months have passed since the third dose.

- These are the residents who are most at risk of being seriously affected if they become infected.

It is important that they receive their fourth dose and strengthen their protection against the disease, says vaccination coordinator Kristine Rygge. 

Up to and including week 5, three doses had been given to approximately 87 percent of residents aged 80 and older in Västra Götaland.