The cases spread across several departments and are currently being investigated by the Work Environment Agency.
On the institution's Facebook page, it reads "With reference to the serious situation of infection, we have decided to extend our closure until June 12, 2021. The date may change further depending on the development.
"Our stage misses its beloved audience, but don't despair - you are warmly welcome here as soon as we open the gates again! Stage art is more important than ever for many, as it brings comfort and joy when we need it most. Therefore, we will regularly fill our digital stage with new and exciting content that you can experience at any time and from any screen at www.operanplay.se."
This occurrence is similar to the one Teatro Real in Madrid overcame when they had 24 COVID-19 cases across several departments.