OBJECTIVE: To present the current epidemiological challenges associated with pertussis and to analyse the factors responsible for the global and national increase in incidence, with particular emphasis on waning vaccine-induced immunity, shifts in the age profile of patients, diagnostic problems, and the impact of the COVID-19 pandemic. SUBJECT AND METHODS: A structured narrative review was conducted. PubMed and Scopus were the principal bibliographic databases; ScienceDirect and Google Scholar were used as supplementary sources. The search was completed on 13 July 2026. One reviewer selected the evidence, and no formal risk-of-bias assessment was performed. Polish surveillance data were reanalysed using official annual surveillance bulletins. RESULTS: The observed increase in pertussis incidence is multifactorial in nature. Key causes include: the gradual waning of post-vaccination immunity, a shift in the patient age profile towards adolescents and adults, underdiagnosis of atypical infections, and the genetic and antigenic evolution of the pathogen. Non-pharmaceutical interventions during the COVID-19 pandemic temporarily reduced bacterial transmission; however, following their lifting, a sharp increase in the number of notifications was recorded. The assessment of the true scale of the problem is also significantly influenced by changes in surveillance systems and improved availability of diagnostic methods. CONCLUSIONS: Effective control of pertussis requires maintaining high population vaccination coverage, implementing prenatal vaccination strategies, and administering regular booster doses. It is essential to optimise laboratory diagnostics, continuously monitor the genetic changes of Bordetella pertussis, and conduct further research to improve epidemiological surveillance programmes.