O'Sullivan Tierney, Keegan Lindsay T
Department of Population Health Sciences, University of Utah School of Medicine, Salt Lake City, UT, 84108, USA.
Division of Epidemiology, Department of Internal Medicine, University of Utah School of Medicine, Salt Lake City, UT, 84108, USA.
BMC Glob Public Health. 2025 May 2;3(1):40. doi: 10.1186/s44263-025-00156-8.
Diphtheria has been re-emerging around the world at alarming rates, raising concerns about emergency preparedness, especially when global supplies of life-saving diphtheria antitoxin are insufficient. Outbreaks have occurred in areas with suboptimal coverage of the three-dose diphtheria tetanus and pertussis (DTP3) vaccine and regions experiencing conflict, but systematic studies assessing the association between these variables and the risk of diphtheria emergence are limited. This population-level study investigated the relationship between fatalities from armed conflict, childhood DTP3 vaccination coverage, and the presence of reported diphtheria cases in countries in the World Health Organization's (WHO) African region from 2017 to 2024.
The analysis was conducted at a subnational geographic scale (I countries = 35, N subnational regions = 541). Data sources include DTP3 coverage from the Demographic Health Surveys (DHS), conflict-related fatalities from the Armed Conflict Location and Event Database (ACLED), and diphtheria cases from the WHO. We first assessed whether a history of fatalities from armed conflict is a predictor of childhood DTP3 coverage using mixed-effects beta regression. To assess the relationship between conflict and diphtheria emergence, we fit a crude logistic regression model to assess their overall association in the study period, as well as repeated measures mixed-effects models to estimate the relationship between time-varying rates of conflict-related fatalities and diphtheria status, adjusting for diphtheria vaccine coverage estimates.
Conflict and subsequent childhood DTP3 vaccine coverage were negatively associated (odds ratio [OR] = 0.93, 95% CI 0.88-0.98). Conflict is also a significant predictor of diphtheria presence, both in the crude (OR = 1.41, 95% CI 1.17-1.68) and best-fitting repeated measures model (OR = 30.30, 95% CI 23.30-39.39), though risk varied by location. The best-fit model also associated lower estimates of diphtheria risk in areas with high (> 80%) and low (< 25%) vaccine coverage, though this is possibly due to underreporting of the true burden of disease in low-resource settings.
This exploratory analysis indicates that conflict-related fatalities are potentially helpful indicators of subnational diphtheria risk in countries in the WHO African region from 2017 to 2024. Further, it may be especially useful in cases where estimates of population-level diphtheria immunity are limited.
白喉在全球范围内正以惊人的速度再度出现，这引发了人们对应急准备的担忧，尤其是在全球救命的白喉抗毒素供应不足的时候。在三剂次白喉、破伤风和百日咳（DTP3）疫苗接种覆盖率不理想的地区以及经历冲突的地区都发生了疫情，但评估这些变量与白喉出现风险之间关联的系统性研究有限。这项基于人群的研究调查了2017年至2024年期间世界卫生组织（WHO）非洲区域各国武装冲突造成的死亡、儿童DTP3疫苗接种覆盖率与报告的白喉病例存在情况之间的关系。
分析在次国家级地理尺度上进行（I个国家 = 35个，N个次国家级区域 = 541个）。数据来源包括人口健康调查（DHS）中的DTP3覆盖率、武装冲突地点和事件数据库（ACLED）中的与冲突相关的死亡人数以及WHO的白喉病例数据。我们首先使用混合效应β回归评估武装冲突造成的死亡史是否是儿童DTP3覆盖率的预测因素。为了评估冲突与白喉出现之间的关系，我们拟合了一个简单逻辑回归模型来评估它们在研究期间的总体关联，以及重复测量混合效应模型来估计随时间变化的与冲突相关的死亡率和白喉状况之间的关系，并对白喉疫苗覆盖率估计值进行了调整。
冲突与随后的儿童DTP3疫苗接种覆盖率呈负相关（优势比[OR] = 0.93，95%置信区间0.88 - 0.98）。冲突也是白喉存在的一个重要预测因素，在简单模型中（OR = 1.41，9%置信区间1.17 - 1.68）以及最佳拟合的重复测量模型中（OR = 30.30，95%置信区间23.30 - 39.39）均是如此，尽管风险因地点而异。最佳拟合模型还表明，在疫苗接种覆盖率高（>80%）和低（<25%）的地区，白喉风险估计值较低，不过这可能是由于资源匮乏地区疾病真实负担报告不足所致。
这项探索性分析表明，在2017年至2024年期间，与冲突相关的死亡人数可能是WHO非洲区域各国次国家级白喉风险的有用指标。此外，在人群层面白喉免疫力估计有限的情况下，它可能特别有用。
