Introduction: The incidence of infectious diseases directly reflects the realities in all spheres of public life. Objective: to describe and analyse the dynamics of infectious morbidity in the country and the Pleven region against the background of fundamental changes in the general socio-economic plan and specific changes in the health sector over 20 years (2004–2023). Material and methods: A retrospective study on the incidence of infectious diseases in Bulgaria and the Pleven region for a 20-year period (2004–2023) was conducted. We used the following sources of information: official population statistics from the National Statistical Institute; official statistics from the National Center for Public Health and Analysis (NCPHA); analysis of the incidence of infectious diseases in the National Center for Infectious and Parasitic Diseases (NCCPD), annual reports of Regional Health Inspectorate – Pleven. Results: Significant changes were found in the incidence of specific infectious diseases related to changes in the immunisation strategy, the entry into force of the health reform at the beginning of the 21st century, and the admission of Bulgaria to the European Union. The impact of the COVID-19 pandemic on the actual reporting of infectious (and not only) morbidity is also evident. Conclusion: There is a permanent trend of decrease in the incidence of infectious diseases in the country and the Pleven region, most pronounced in diseases with mass vaccine prophylaxis. Follow-up in the dynamics of infectious diseases is a sensitive indicator of public health at the national and regional levels.

Bulgaria, immunisation calendar, infectious diseases incidence, Pleven region