This is a garbage study. I had a covid. It’s a 2-3 day cold. Period. If those infected with covid have increased stress/depression/anxiety it’s got far less to do with the virus itself and far more to do with exhaustion with all the pandemic b-llsh-t of vaxxes and masks and lockdowns and quarantines and restrictions.
My wife and I are on the better side of having covid and we were pretty miserable for a couple weeks. And we’re still dragging ass. But we ain’t mentally ill. You get sick and then you get well. Sometimes take longer than others.