Wellcome Trust Research Laboratory, Department of G.I. Sciences, Christian Medical College Vellore, Vellore, India.
MRC Clinical Trials Unit, University College London, London, UK.
Trials. 2023 Aug 3;24(1):492. doi: 10.1186/s13063-023-07555-y.
Typhoid fever causes nearly 110,000 deaths among 9.24 million cases globally and disproportionately affects developing countries. As a control measure in such regions, typhoid conjugate vaccines (TCVs) are recommended by the World Health Organization (WHO). We present here the protocol of a cluster randomised vaccine trial to assess the impact of introducing TyphiBEV® vaccine to those between 1 and 30 years of age in a high-burden setting.
The primary objective is to determine the relative and absolute rate reduction of symptomatic, blood-culture-confirmed S. Typhi infection among participants vaccinated with TyphiBEV® in vaccine clusters compared with the unvaccinated participants in non-vaccine clusters. The study population is residents of 30 wards of Vellore (a South Indian city) with participants between the ages of 1 and 30 years who provide informed consent. The wards will be divided into 60 contiguous clusters and 30 will be randomly selected for its participants to receive TyphiBEV® at the start of the study. No placebo/control is planned for the non-intervention clusters, which will receive the vaccine at the end of the trial. Participants will not be blinded to their intervention. Episodes of typhoid fever among participants will be captured via stimulated, passive fever surveillance in the area for 2 years after vaccination, which will include the most utilised healthcare facilities. Observers blinded to the participants' intervention statuses will record illness details. Relative and absolute rate reductions will be calculated at the end of this surveillance and used to estimate vaccine effectiveness.
The results from our trial will allow countries to make better-informed decisions regarding the TCV that they will roll-out and may improve the global supplies and affordability of the vaccines.
Clinical Trials Registry of India (CTRI) CTRI/2022/03/041314. Prospectively registered on 23 March 2022 ( https://ctri.nic.in/Clinicaltrials/pmaindet2.php?trialid=62548&EncHid=&userName=vellore%20typhoid ). CTRI collects the full WHO Trial Registration Data Set.
伤寒在全球 924 万例病例中导致近 11 万人死亡，且不成比例地影响发展中国家。作为这些地区的控制措施，世界卫生组织（WHO）建议使用伤寒结合疫苗（TCV）。我们在此介绍一项群组随机疫苗试验的方案，以评估在高负担地区向 1 至 30 岁人群引入 TyphiBEV®疫苗的效果。
主要目的是确定在疫苗群组中接种 TyphiBEV®的参与者与非疫苗群组中未接种疫苗的参与者相比，症状性、血培养确诊的 S. Typhi 感染的相对和绝对发病率降低率。研究人群是维洛尔（印度南部城市）的 30 个区的居民，年龄在 1 至 30 岁之间，他们提供了知情同意。这些区将被分为 60 个连续的群组，其中 30 个将被随机选择，其参与者将在研究开始时接种 TyphiBEV®。非干预群组不计划使用安慰剂/对照，将在试验结束时接种疫苗。参与者不会对他们的干预措施感到盲目。接种疫苗后 2 年内，通过该地区的强化被动发热监测来捕捉参与者的伤寒病例，这将包括最常用的医疗设施。对参与者干预状态不知情的观察员将记录疾病详情。在监测结束时，将计算相对和绝对发病率降低率，并用于估计疫苗效力。
我们的试验结果将使各国能够更好地就他们将推出的 TCV 做出明智的决策，并可能改善疫苗的全球供应和可负担性。
印度临床试验注册中心（CTRI）CTRI/2022/03/041314。于 2022 年 3 月 23 日前瞻性注册（https://ctri.nic.in/Clinicaltrials/pmaindet2.php?trialid=62548&EncHid=&userName=vellore%20typhoid）。CTRI 收集完整的世卫组织试验注册数据集。
