Measles and vaccination against it: problems and prospects

Background. Measles remains a major public health concern due to its high contagion rate and the increasing number of outbreaks in recent years despite the long-standing vaccination programs. This narrative review examines recent epidemiological data and vaccine coverage trends in Europe and selected Eurasian countries, with a focus on the effectiveness and challenges of measles immunization strategies. Methods. Relevant literature from 2014 to 2024 was reviewed using international and regional medical databases (e.g., eLibrary.ru, PubMed). Studies were selected based on keywords related to measles epidemiology, vaccine (in)effectiveness, immune response durability, and immunological phenomena such as waning immunity and immune imprinting. Results. The review highlights inconsistencies in measles case reporting, gaps in surveillance, and the persistence of measles outbreaks despite high vaccination rates in some regions. It also discusses the structure and immunogenicity of the measles virus, herd immunity thresholds, and possible factors contributing to vaccine failure, including waning immunity and individuals with primary vaccine failure (non-responders). This review critically examines the strengths and limitations of current vaccination strategies and reporting systems. It emphasizes the importance of balanced interpretation of available data and the need for further large-scale, independent studies. Improved diagnostics, transparent public health communication, and robust immunization monitoring systems are essential for effective measles control. Phenomena identified more than half a century ago, such as immune imprinting and antibody-dependent enhancement (ADE), are also discussed, as these remain areas of active investigation. Conclusion. While the measles vaccine remains one of key tools in disease control, evolving epidemiological patterns suggest the need to reassess current immunization schedules and consider complementary strategies. Further research is essential to clarify the mechanisms of breakthrough infections and to optimize long-term protection.