MENINGOCOCCAL DISEASE: DO WE HAVE ADEQUATE PREVENTION OR CAN WE IMPROVE?

Abstract

Meningococcal disease is characterized by epidemiological variability and unpredictable behavior in different regions of the world. Vaccination has proven to be one of the most effective strategies to reduce the incidence of the disease. Currently, various meningococcal vaccine platforms are available, including polysaccharide, conjugate, and outer membrane protein-based vaccines. Among them, the tetravalent conjugate vaccines MenACWY have shown high effectiveness, not only providing direct protection to vaccinated groups but also indirect protection by reducing nasopharyngeal carriage, particularly in adolescents. In Chile, a reduction of up to 92% in MD incidence was observed after the introduction of this vaccine. Regarding vaccines against se- rogroup B, two formulations have been developed: 4CMenB and MenB-FHbp, both effective against this serogroup. However, these vaccines do not eliminate nasopharyngeal carriage. Additionally, studies have demonstrated that 4CMenB can indice bactericidal antibodies with cross-protection against other serogroups and up to 46% cross-species protection against Neis- seria gonorrhoeae. More recently, pentavalent vaccines (MenABCWY and MenACWXY) have been developed, offering broader coverage against multiple serogroups, which promises a greater global impact on MD prevention and improved adherence to immunization programs. The implementation of vaccination schedules depends on local epidemiology, the coverage achieved, the characteristics of the immunization program, and the available resources. Strengthening epidemiological surveillance is essential to dynamically adjust vaccination strategies and detect early changes in serogroup circulation.