EVALUATION AND EFFECTIVENESS OF VACCINATION IN THE PREVENTION OF THE OUTBREAK OF INFECTIOUS DISEASES AMONG UNDER FIVE YEARS CHILDREN IN MATTRU DISTRICT OF SIERRA LEONE

ABSTRACT Vaccination is a key public health intervention for reducing morbidity and mortality from infectious diseases, particularly among children under five years old. In Mattru District, Sierra Leone, the burden of vaccine-preventable diseases has historically posed a significant challenge to child health. This study evaluates the effectiveness of vaccination in preventing outbreaks of infectious diseases among children under five in this region. To assess the impact of vaccination programs in reducing the incidence of vaccine-preventable diseases and to identify factors influencing vaccination coverage and effectiveness. The study employed a mixed-methods approach, combining quantitative analysis of vaccination coverage data and disease incidence trends with qualitative insights from caregivers and healthcare providers. data were collected from health facility records, vaccination cards, and interviews with stakeholders in the district. Key indicators included vaccination coverage rates, outbreak reports, and awareness levels among caregivers. The findings indicate a significant reduction in outbreaks of diseases such as measles, polio, and tuberculosis among vaccinated children. Vaccination coverage among children under five in Mattru District was estimated 390 (83%%) had taken their children for DPT with geographic disparities observed in rural versus urban areas. Challenges identified include vaccine stockouts, inadequate healthcare infrastructure, and vaccine hesitancy due to misinformation. Despite these challenges, vaccinated children demonstrated higher resilience against infectious disease outbreaks compared to their unvaccinated peers. Vaccination programs in Mattru District have effectively reduced the incidence of infectious diseases among children under five, though barriers to full coverage persist. Strengthening healthcare delivery systems, enhancing community education, and addressing logistical constraints are critical for sustaining and improving vaccination effectiveness. Key Words; Vaccination, Prevention, Infectious, Diseases, Outbreak INTRODUCTION Immunization describes the whole process of delivering a vaccine and the immunity it generates in an individual and population. It remains the most cost effective and important public health strategy for disease prevention. Vaccine preventable infectious diseases such as tuberculosis, poliomyelitis, diphtheria, tetanus and measles are the main causes of morbidity and mortality in children especially in developing countries (David & Marty, 2010). According to a report by the World Health Organization (2007), global vaccination coverage has stagnated below the 90% target for more than a decade, meaning that a significant proportion of the global annual birth cohort remains unvaccinated with DTP3. The Millennium Development Goals (MDGs) are eight international development goals that were officially established following the Millennium Summit of the United Nations in 2000, following the adoption of the United Nations Millennium Declaration,MDG4 is one of the eight goals which was to reduce under five mortality rates by two third between 1990 and 2015 (WHO Fact Sheet, 2014) .To reduce unnecessary child death, Integrated Management of Childhood Illness Strategy was implemented, which includes immunization, one of the most effective interventions in reducing child mortality (Adut, 2012)