Abstract: The instant invention relates to a process in which important improvements are introduced in virus production and inactivation steps, as well as in the vaccine formulation step. The virus is reproduced in animals immuno-depressed through ionizing radiations, thus making it possible to use adult host animals, not naturally sensitive to the virus, with the advantage of using all types of tissues thereof. Bacterial infections are prevented by antibiotic administration. Virus inactivation is also obtained through ionizing radiations. Radiation doses do not affect antigenic properties, as may be noted from the interpretation of the Target Theory.