Olympic swimmer Madi Wilson says she was hospitalized with COVID-19 "as a precautionary measure" while in Italy for an International Swimming League (ISL) event.Wilson, who won gold with Australia in the 4x100m freestyle relay at the Tokyo Olympics two months ago, says she is fully vaccinated. In a series of posts on Instagram, she encouraged others to also get vaccinated against COVID-19."I just wanted to jump on here and say a massive thank you to everyone again for the messages of support. I am so grateful for every single one of you reaching out and looking after me. The ISL and Swimming Australia have been incredible to me," said 27-year-old Wilson."Mostly I just wanted to jump on and continue to encourage people to get vaccinated. I did end up in the hospital, but that is as a precautionary because I do have underlying chest and lung issues."It (the vaccine) protected the people around me who I've been close to over this last period of time and I am so grateful for that because I would not want anyone else in this situation. I truly believe it reduced what happened to me and what could happen to me," Wilson said.Wilson competes for the LA Current and was unable to race in Match 8 of the ISL season in Naples after returning a positive COVID-19 test.On top of her 4x100m freestyle gold, she also won bronze in the 4x200m freestyle relay in Tokyo."It's been a crazy few months and I believe being run down physically and mentally may have made me more susceptible," Wilson wrote in an Instagram post on Sunday."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."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," Wilson said.In a separate Instagram post on Sunday, Wilson said she "already feel(s) so much better" and that "the biggest thing I can say is please get vaccinated."