Powdery mildew a risk to my chids?

[let_it_grow]

My grandmother got me a mini rose with beautiful tiny flowers and another lovely surprise... POWDERY MILDEW. I had the rose on a shelf with my chids when i noticed it. I tried spraying with a mixture of peroxide and water and a tiny bit of soap and it seemed to work but soon after i noticed it came back so i got fed up and cut every single leaf off the rose in an attempt to save it (i think it worked and i didnt kill the rose... hardy little fella) but i just saw that my NOID Onc looks like it has a bit on some new growth, i sprayed it with the peroxide, soap, water mixture and I havent seen any come back after a few weeks. Do i need to be overly concerned? I know some plants are really prone to powdery mildew and it can spread quick but i have never seen it on chids. I havent seen any signs of it on my other chids, the Onc was sitting just beside the rose so I think thats why it got hit. Should i be a 1/10 on the worry scale or a 10/10?