Can a cat get a shot for worms?

Yes your cat can be spayed even though she has worms. Set up an appointment with your Vet to have her spayed and in the mean time bring in a sample of her feces and the worm too. Roundworms look like spaghetti, long and thin. Tapeworms look like little grains of rice. She could have other parasites too that you cannot see such as hookworms, whipworms, etc., so that is the reason to bring in a sample of her feces so the Vet can check it out. Make sure she has had her vaccinations too, if not, then have the Vet tell you what is needed & he will set her up on a schedule for her vaccinations. She could be dewormed then and again in 10-14 days.