I just saw on the local Knoxville news that GSMNP is temporarily changing their policy for backcountry shelters to allow visitors to set up a tent around the shelter. Due to the Carona Virus, they are recommending that people NOT stay in the shelters.
They also said that all visitor centers, meeting areas, and campground kiosks are closed, but restrooms will be open. The park is open for camping and hiking, just don't expect to talk to any employees other than rangers.