“Sending you all love and prayers for him to get better soon,” another social media user said.
A third added: “Nothing worse when your kids are poorly, staying strong, praying for a speedy recovery of your beautiful son.”
Harvey was rushed to hospital at the weekend with a raised temperature, one of the symptoms of the coronavirus.
She said in an earlier post that she was unable to be by her son’s beside because of the current restrictions to prevent the spread of COVID-19.
Katie told followers: “It’s hard as due to limited visiting hours and covid I can’t be by his bed side, but he is being brave and strong, and able to facetime him, I’ve let him know he has so much love and support.”
The reality star, who is also mum to Junior, 15, and Princess, 13, who she shares with ex husband Peter Andre, as well as Jett, six, and Bunny, five , with her third husband Kieran.