If a dog has been infected with parvovirus and successfully recovered, his body will usually produce antibodies against the virus, thus gaining immunity over a period of time , reducing the possibility of reinfection. However, this immunity is not permanent and over time, antibody levels may decrease and immunity may wane.

The duration of immunity to parvovirus varies between individuals, and is generally believed to last from several months to several years. Therefore, even if a dog has had parvovirus in the past, it is still possible to get it again after the dog's immunity has weakened. To maintain your dog's immunity, regular vaccination against parvovirus is a very important preventive measure. Vaccines stimulate your dog’s immune system to produce antibodies that help them fight off parvovirus.