The former Australian champion still believes he can add to his three Grand Slams, despite battling the virus, hotel quarantine and relative old age.
“I’m trying to get in shape. I was positive over Christmas so I had to stay more than 10 days at home, so I completely lost all the work I did off-season,” added Wawrinka.
“I was feeling really bad during the first five days but the symptoms, you keep it, and are more tired every day and that lasts a few weeks.
“It was not a good experience. Now I finally start to feel better but it can touch you badly and it’s important to be really careful.”
The former Australian champion will be searching for his first title since Geneva in 2017 at the Australian Open 2021 which is set to start on Feb 8.