Olympic gold medallist Madi Wilson has been admitted to hospital while battling Covid-19.

Currently in Naples, Italy, for the International Swimming League, Ms Wilson was moved into hospital on September 18, explaining to fans that doctors wanted to treat her and keep her under observation.

A fit and healthy 27-year-old, she won a gold medal in the women's 4x100 metre freestyle relay at the Tokyo Olympics just weeks ago, swimming alongside fellow superstars Bronte Campbell and Meg Harris. 

The swimming star was fully-vaccinated prior to the Tokyo games in August, but believes the physical and mental effects of a packed year of racing contributed to her infection. 

Ms Wilson currently swims for the Los Angeles Currents alongside Aussies Bronte Campbell and Matt Wilson, but will miss match 8 of the competition after her diagnosis. 

'I recently tested positive for Covid and yesterday was moved into hospital for further care and observation,' Ms Wilson wrote in an Instagram post on Sunday.

'Even though I am double vaccinated and took the right precaution set in place through the ISL, I have managed to fall to this virus. 

'It's been a crazy few months and I believe being run down physically and mentally may have made me more susceptible.

'I feel extremely unlucky but I do believe this is a huge wake-up call, Covid is a serious thing and when it comes it hits very hard.'

But just like anyone, the super fit Olympic star admitted that she was frightened by the virus ravaging the world.

'I'd be stupid not to say I wasn't scared. I'm so lucky for all my family, friends and support people. I can't believe how much love I have been shown and I'm forever in debt to these people,' she wrote.