Emerg Infect Dis. 2023 Jan;29(1):70-80. doi: 10.3201/eid2901.220975.
In 2019, a community-based, cross-sectional carriage survey and a seroprevalence survey of 1,216 persons 1-55 years of age were conducted in rural Vietnam to investigate the mechanism of diphtheria outbreaks. Seroprevalence was further compared with that of an urban area that had no cases reported for the past decade. Carriage prevalence was 1.4%. The highest prevalence, 4.5%, was observed for children 1-5 years of age. Twenty-seven asymptomatic Coerynebacterium diphtheriae carriers were identified; 9 carriers had tox gene-bearing strains, and 3 had nontoxigenic tox gene-bearing strains. Child malnutrition was associated with low levels of diphtheria toxoid IgG, which might have subsequently increased child carriage prevalence. Different immunity patterns in the 2 populations suggested that the low immunity among children caused by low vaccination coverage increased transmission, resulting in symptomatic infections at school-going age, when vaccine-induced immunity waned most. A school-entry booster dose and improved infant vaccination coverage are recommended to control transmissions.
2019 年，在越南农村地区进行了一项基于社区的、横断面的带菌者调查和一项针对 1216 名 1-55 岁人群的血清流行率调查，以研究白喉暴发的机制。进一步将血清流行率与过去十年无病例报告的城市地区进行了比较。带菌率为 1.4%。最高的流行率为 4.5%，发生在 1-5 岁的儿童中。发现了 27 名无症状的白喉棒状杆菌携带者；9 名带菌者携带毒基因菌株，3 名带非致毒株毒基因菌株。儿童营养不良与白喉类毒素 IgG 水平低有关，这可能随后增加了儿童带菌率。两个人群的不同免疫模式表明，由于疫苗接种覆盖率低导致儿童免疫力低下，增加了传播，导致学龄期出现症状性感染，此时疫苗诱导的免疫力下降最明显。建议接种入学加强针和提高婴儿疫苗接种覆盖率以控制传播。
