Andersson, 54, is one of several party leaders to have tested positive for the virus in the wake of a debate in parliament earlier this week while Sweden's king, queen and crown princess have all been hit with infections this month.
The Nordic country has repeatedly set new daily records for COVID cases this month amid a mounting fourth wave of the virus, raising pressure on the healthcare system and triggering the reimposition of many restrictions.
"She (Andersson) is following the current recommendations and will perform her duties from home. The PM is feeling well, given the situation," the spokesperson said.
The health agency expects cases, currently hitting highs of around 25,000 per day, to peak later this month when Sweden could reach almost 70,000 daily cases, according to its modeling.
(Reporting by Niklas Pollard, Simon Johnson and Johan Ahlander)
