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

Abstract

Despite the availability of effective vaccines, diphtheria is still a major public health problem. The aim of this narrative review was to examine the global trend of diphtheria cases and their regional disparities, as well as the issues of vaccine hesitancy, diphtheria surveillance, and public health interventions. This narrative review aims to summarize current global trends in diphtheria surveillance and vaccination coverage based on reports from the World Health Organization (WHO), UNICEF, the European Centre for Disease Prevention and Control (ECDC), and peer-reviewed literature from PubMed and Scopus, published in English from 2000 to 2023. This narrative review shows that there are significant regional differences in diphtheria burden, with higher rates in Africa and Southeast Asia, where vaccination coverage is low, compared to Europe and North America, where strong immunization programs have been in place, resulting in the near-elimination of diphtheria. However, outbreaks are underreported, data is incomplete, and laboratory capacity is limited, which impairs the timely response to outbreaks, especially in low-resource countries. The global control efforts are complicated by vaccine hesitancy, geopolitical issues, and surveillance gaps. High vaccination coverage is important to reach herd immunity and to minimize disease rates. To improve outcomes, in addition to strengthening vaccination strategies, there is a need for community engagement and targeted vaccination campaigns, as well as for strengthening laboratory infrastructure and effective data collection. This narrative review highlights the importance of strengthening vaccination strategies, strengthening surveillance, and targeted interventions for the control of diphtheria and other vaccine-preventable diseases.