Global Diphtheria Trends and Regional Disparities: A Narrative Review of the Influence of Vaccine Hesitancy, Surveillance Gaps, and Public Health Interventions

Diphtheria remains a significant public health concern despite effective vaccines. This narrative review examines global trends in diphtheria incidence, with a focus on regional disparities, vaccine hesitancy, surveillance challenges, and public health interventions. This narrative review synthesizes global trends in diphtheria surveillance and vaccination coverage, drawing on reports from the World Health Organization (WHO), UNICEF, regional health organizations (e.g., ECDC, PAHO), and peer-reviewed literature from PubMed and Scopus, published in English between 2000 and 2023. This narrative review highlights marked regional disparities in diphtheria incidence, with higher burdens in Africa and Southeast Asia due to low vaccination coverage, in contrast to near-elimination in Europe and North America, where robust immunization programs have been implemented. Despite effective surveillance in some countries, underreporting, incomplete data, and inadequate laboratory capacity hinder timely responses to outbreaks, particularly in low-resource settings. Vaccine hesitancy, geopolitical factors, and surveillance gaps further complicate global control efforts. High vaccination coverage is crucial for achieving herd immunity and reducing the incidence of diseases. Community engagement and targeted vaccination campaigns are crucial for enhancing outcomes, alongside the implementation of enhanced vaccination strategies, robust laboratory infrastructure, and effective data collection practices. This narrative review underscores the need for enhanced vaccination strategies, improved surveillance, and targeted interventions to address diphtheria and other vaccine-preventable diseases.