Canine Distemper Vaccine. Modified Live Virus.  For the vaccination of healthy dogs as an aid in the prevention of disease caused by canine distemper. Inject one dose (1mL) subcutaneously or intramuscularly. The initial dose is given at 6 weeks of age or older. Repeat at 2-4 week intervals until the dog is 12 weeks of age. A minimum of 2 doses is required for primary immunization. Annual revaccination with 1 dose is recommended. Do not vaccinate pregnant bitches.