A kit, a method of using it and a process for preparing a vaccine for immunization against the disease Porcine Circovirus Disease and/or Enzootic Pneumonia in pigs are proposed, in which a first container is only partly filled with a first vaccine and a second container is filled with a second vaccine, the second vaccine being transferred into the first container through an adapter device, when a closure device is penetrated for the first and/or only time, and the vaccinating agent is prepared therein, thus making the operation simple, less error-prone and more hygienic, while reducing the materials required. The adapter device has a pair of oppositely facing piercing elements formed of one of needles, hollow, spikes, wedges with at least one through passage extending through both piercing elements, each of the containers being pierced by a respective one of the piercing elements creating a fluid connection between the containers.
