Khanam Farhana, Rickett Natasha Y, Ahmmed Faisal, Islam Md Taufiqul, Mbae Cecilia Kathure, Im Justin, Aziz Asma Binte, Ongadi Beatrice, Chowdhury Fahima, Khan Ashraful Islam, Akter Afroza, Firoj Md Golam, Rahman Sadia Isfat Ara, Haile Kassa, Park Se Eun, Mwebia Martin Bundi, Mwangi Moses, Ngugi Benjamin, Behute Meseret Gebre, Kering Kelvin, Agampodi Suneth, Kanungo Suman, Liu Xinxue, Pollard Andrew J, Zaman K, Kim Deok Ryun, Kariuki Samuel, Qadri Firdausi, Clemens John D
International Centre for Diarrhoeal Disease Research, Dhaka, Bangladesh.
International Vaccine Institute, Clinical, Assessment, Regulatory, Evaluation Unit (CARE Unit), Seoul, Republic of Korea.
BMC Infect Dis. 2025 Jan 31;25(1):149. doi: 10.1186/s12879-025-10548-8.
When delivered through vaccination Vi-polysaccharide antigen of Salmonella enterica serotype Typhi protects against typhoid by inducing IgG anti-Vi antibodies. We aimed to determine whether the presence of antibodies following natural infection is associated with a lower incidence of typhoid fever in endemic regions.
We analyzed data from a cohort study of typhoid fever conducted in Dhaka, Bangladesh. Plasma IgG anti-Vi antibodies were measured using a standard enzyme-linked immunosorbent assay in random serosurveys of a population that had not previously received typhoid vaccination. Participants were followed for up to 20 months for culture-confirmed typhoid fever. The receiver operating characteristic (ROC) curve and Cox proportional hazard models were used to evaluate the associations between antibody levels and typhoid risk.
The ROC analysis revealed that IgG anti-Vi antibody titers were predictive of typhoid risk among the 8,261 serosurvey participants (area under the curve: 0·63; 95% confidence interval (CI): 0·58─0·67). Detection of any antibodies was associated with a lower risk of typhoid in crude analyses (hazard ratio (HR): 0·13; 95% CI: 0·03─0·52), though this association declined after adjustment (HR: 0·32; 95% CI: 0·07─1·40). A positive correlation was observed between IgG anti-Vi titers and age (correlation coefficient 0·35; p < 0·001), with a stepwise increase in detectable antibodies by age, ranging from 12·0% (280/2,333) in children under 5 years to 54·2% (463/854) in individuals 50 years and older (p < 0·001).
In typhoid-endemic populations, IgG anti-Vi antibodies may indicate natural immunity to typhoid. The increasing seroprevalence with age suggests that these antibodies could serve as markers of cumulative past typhoid infections. Future research should explore these possibilities.
Not applicable.
通过接种疫苗递送时，伤寒沙门菌Typhi血清型Vi多糖抗原通过诱导IgG抗Vi抗体预防伤寒。我们旨在确定自然感染后抗体的存在是否与流行地区伤寒热的较低发病率相关。
我们分析了在孟加拉国达卡进行的一项伤寒热队列研究的数据。在对先前未接种伤寒疫苗的人群进行的随机血清学调查中，使用标准酶联免疫吸附测定法测量血浆IgG抗Vi抗体。对参与者进行长达20个月的随访，以确定培养确诊的伤寒热。采用受试者工作特征（ROC）曲线和Cox比例风险模型评估抗体水平与伤寒风险之间的关联。
ROC分析显示，在8261名血清学调查参与者中，IgG抗Vi抗体滴度可预测伤寒风险（曲线下面积：0·63；95%置信区间（CI）：0·58─0·67）。在粗分析中，检测到任何抗体与较低的伤寒风险相关（风险比（HR）：0·13；95%CI：0·03─0·52），尽管调整后这种关联有所下降（HR：0·32；95%CI：0·07─1·40）。观察到IgG抗Vi滴度与年龄呈正相关（相关系数0·35；p < 0·001），随着年龄的增长，可检测到的抗体呈逐步增加，从5岁以下儿童的12·0%（280/2333）到50岁及以上个体的54·2%（463/854）（p < 0·001）。
在伤寒流行人群中，IgG抗Vi抗体可能表明对伤寒的自然免疫力。随着年龄增长血清阳性率增加表明这些抗体可作为既往累积伤寒感染的标志物。未来研究应探索这些可能性。
不适用。
