"He is recovering. The first few days are critical when you have corona, and while he has symptoms, they are pretty mild. Racing becomes a second priority. His priority now is getting healthy."
Hamilton, 35, came into contact with an infected person following a holiday in Dubai in the days before last weekend's race in Bahrain.
It leaves the world champions without their £40 million-a-season ($NZ76.3m) driver for one, possibly two races, but Wolff added: "Lewis doesn't need any permission to go to Dubai.
"He rides anything he wants, and jumps out of every airplane he wants, because he knows what is best for him. He is a grown-up man and this was never an issue."
Hamilton's enforced absence provides Russell with the opportunity of a lifetime. A Williams driver by day, Russell has been promoted to a seat in the fastest car in F1 history.
From King's Lynn in Norfolk, Russell is yet to score a point in his two seasons in the sport but he will head into Monday's race among the favourites to win.
The Englishman, 22, finished quickest on a new configuration of the Bahrain International Circuit, lapping the 2.17-mile track in 54.5 seconds, 0.176 sec clear of Red Bull's Max Verstappen and an impressive three tenths ahead of team-mate Valtteri Bottas.
Later in the day, Russell topped the time charts again, with Bottas even further back in 11th after his best effort was deleted for exceeding track limits.
Russell, who discovered he could replace Hamilton following a 2am bathroom phone call from Wolff on Tuesday, is a member of Mercedes' young driver academy. He persuaded Wolff to sign him with the help of a PowerPoint presentation when he was still a teenager.
"George is totally relaxed," added Wolff. "He comes across on the radio as chatty and buzzing, but he is very focused, and calm.
"The record he has of winning the GP3 and F2 championships, both in his rookie years, stand out.
"I remember he came to my office when he was 15 or 16 and he was wearing a black suit and a black tie with a PowerPoint presentation as to why Mercedes should support his career.
"He is very mature for his age and his personality is well-suited to jump in the car in such a high-pressure situation. But let us keep both feet on the ground. These cars have not been taken out in anger yet."
- Daily Telegraph UK
