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Abstract：
Lassa fever (LF), a haemorrhagic illness caused by the Lassa fever virus (LASV), is endemic in West Africa and causes 5000 fatalities every year. The true prevalence and incidence rates of LF are unknown as infections are often asymptomatic, clinical presentations are varied, and surveillance systems are not robust. The aim of the Enable Lassa research programme is to estimate the incidences of LASV infection and LF disease in five West African countries. The core protocol described here harmonises key study components, such as eligibility criteria, case definitions, outcome measures, and laboratory tests, which will maximise the comparability of data for between-country analyses.
We are conducting a prospective cohort study in Benin, Guinea, Liberia, Nigeria (three sites), and Sierra Leone from 2020 to 2023, with 24 months of follow-up. Each site will assess the incidence of LASV infection, LF disease, or both. When both incidences are assessed the LASV cohort (nmin = 1000 per site) will be drawn from the LF cohort (nmin = 5000 per site). During recruitment participants will complete questionnaires on household composition, socioeconomic status, demographic characteristics, and LF history, and blood samples will be collected to determine IgG LASV serostatus. LF disease cohort participants will be contacted biweekly to identify acute febrile cases, from whom blood samples will be drawn to test for active LASV infection using RT-PCR. Symptom and treatment data will be abstracted from medical records of LF cases. LF survivors will be followed up after four months to assess sequelae, specifically sensorineural hearing loss. LASV infection cohort participants will be asked for a blood sample every six months to assess LASV serostatus (IgG and IgM).
Data on LASV infection and LF disease incidence in West Africa from this research programme will determine the feasibility of future Phase IIb or III clinical trials for LF vaccine candidates.
We are conducting a prospective cohort study in Benin, Guinea, Liberia, Nigeria (three sites), and Sierra Leone from 2020 to 2023, with 24 months of follow-up. Each site will assess the incidence of LASV infection, LF disease, or both. When both incidences are assessed the LASV cohort (nmin = 1000 per site) will be drawn from the LF cohort (nmin = 5000 per site). During recruitment participants will complete questionnaires on household composition, socioeconomic status, demographic characteristics, and LF history, and blood samples will be collected to determine IgG LASV serostatus. LF disease cohort participants will be contacted biweekly to identify acute febrile cases, from whom blood samples will be drawn to test for active LASV infection using RT-PCR. Symptom and treatment data will be abstracted from medical records of LF cases. LF survivors will be followed up after four months to assess sequelae, specifically sensorineural hearing loss. LASV infection cohort participants will be asked for a blood sample every six months to assess LASV serostatus (IgG and IgM).
Data on LASV infection and LF disease incidence in West Africa from this research programme will determine the feasibility of future Phase IIb or III clinical trials for LF vaccine candidates.
摘要：
背景：拉沙热（LF），由拉沙热病毒（LASV）引起的出血性疾病，是西非的地方病，每年造成5000人死亡。LF的真实患病率和发病率未知，因为感染通常是无症状的。临床表现多种多样，和监控系统不健全。启用拉萨研究计划的目的是估计五个西非国家的LASV感染和LF疾病的发病率。这里描述的核心协议协调了关键的研究组件，如资格标准，案例定义，结果衡量标准，和实验室测试，这将最大限度地提高国家间分析数据的可比性。
方法：我们正在贝宁进行一项前瞻性队列研究，几内亚,利比里亚,尼日利亚（三个地点），和塞拉利昂，从2020年到2023年，有24个月的随访。每个站点将评估LASV感染的发生率，LF病，或者两者兼而有之。当评估两种发病率时,将从LF群组(nmin=5000/位点)中抽取LASV群组(nmin=1000/位点)。在招募期间，参与者将填写有关家庭组成的问卷，社会经济地位,人口特征，和LF历史，和血液样本将被收集以确定IgGLASV血清状态。LF疾病队列参与者将每两周联系一次，以确定急性发热病例。将从中抽取血液样本，使用RT-PCR检测活跃的LASV感染。症状和治疗数据将从LF病例的医疗记录中提取。LF幸存者将在四个月后进行随访，以评估后遗症，特别是感音神经性听力损失。LASV感染队列参与者将被要求每六个月提供一次血液样本，以评估LASV血清状态（IgG和IgM）。
结论：来自本研究计划的西非LASV感染和LF疾病发病率数据将确定LF候选疫苗未来IIb期或III期临床试验的可行性。
方法：我们正在贝宁进行一项前瞻性队列研究，几内亚,利比里亚,尼日利亚（三个地点），和塞拉利昂，从2020年到2023年，有24个月的随访。每个站点将评估LASV感染的发生率，LF病，或者两者兼而有之。当评估两种发病率时,将从LF群组(nmin=5000/位点)中抽取LASV群组(nmin=1000/位点)。在招募期间，参与者将填写有关家庭组成的问卷，社会经济地位,人口特征，和LF历史，和血液样本将被收集以确定IgGLASV血清状态。LF疾病队列参与者将每两周联系一次，以确定急性发热病例。将从中抽取血液样本，使用RT-PCR检测活跃的LASV感染。症状和治疗数据将从LF病例的医疗记录中提取。LF幸存者将在四个月后进行随访，以评估后遗症，特别是感音神经性听力损失。LASV感染队列参与者将被要求每六个月提供一次血液样本，以评估LASV血清状态（IgG和IgM）。
结论：来自本研究计划的西非LASV感染和LF疾病发病率数据将确定LF候选疫苗未来IIb期或III期临床试验的可行性。
