The standard immunization schedule for the DAPP (distemper, adenovirus, parvovirus, parainfluenza virus) vaccine is as follows. Puppies should begin their vaccination series between 6 and 8 weeks of age and receive shots every 3 to 4 weeks until they are at least 16 weeks of age. The last injection must be given after 14 weeks of age to ensure that the immunity derived from mother’s milk that can inactivate vaccines has a chance to wane. The next booster is given at the dog’s first annual check-up (when the dog is 12 to 16 months old). Thereafter, boosters can be given every three years. In adult dogs with an unclear vaccination history, only one vaccine is needed to start the series, and this can then be boosted every three years from that point on. Some veterinarians may recommend a different schedule based on the severity and incidence of diseases in their location. For more information about vaccines, see this article.