The chances of feline distemper infecting adult cats depend on the situation. If the adult cat is healthy, fully vaccinated and has good antibody tests in its body, the chance of being infected with feline distemper is very low or even not. However, if the adult cat is in poor health and has not been vaccinated, then it will basically be infected. Therefore, when a cat has distemper, it should be isolated and treated promptly, and other cats should be vaccinated and prevented from the disease.
