The Expanded Program on Immunization (EPI) in Chile, was born in 1978, considering within its objectives the prevention of morbidity, disability and deaths secondary to immunoprevenible diseases throughout the entire life cycle. Among the risks associated with the immunization process and that the EPI contemplates since its inception, there are the "Programmatic Errors in Vaccination"(EPRO), defined as attitudes or procedures that do not comply with the established norms of vaccination and that alone or in together they can generate serious and fatal adverse events. The management and prevention of events such as EPROs are vital for the assurance of quality and safety in patient care throughout their life cycle, a task that the Nursing team has been responsible for leading since the beginning of the immunization process in our country and which has been demonstrated through strategies such as process standardization, implementation of safety guidelines throughout the vaccination process, reporting of errors with detailed and truthful information, continuous improvement programs, evaluation of quality guidelines of processes, stock control management systems, teamwork and effective communication methodologies.