Vos is so beautiful. I've used Zithromax with quite good luck treating kitties with pneumonia. I had a very memorable litter some years back, seven kittens born to a nine year old cat I rescued from an irresponsible person. Naturally it was a weekend do pets have a secret thing they do? Wait it out till it's the weekend? but one of the kittens was having very labored breathing, and I knew it was pneumonia...been there, done that through years of rescueing. I luckily had Zithromax on hand to give the gasping kitten, and gave him a small amount of sub-q fluids as well. Supportive treatment got him enough over the hurdle that he was almost 100% by Sunday....enough to be bouncing off the walls with his littermates. What is your vet prescribing? Hope dear Vos makes a complete recovery.