FIELD TRIAL OF ORAL CHOLERA VACCINES IN BANGLADESH

该项目需要对来自大型- B亚单位灭活全细胞的规模、安慰剂对照现场试验 (BS-WC)和灭活全细胞(WC)霍乱口服疫苗， 在1985-90年间，在 孟加拉国国际腹泻病研究中心。这个 试验招募了大约89,000名受试者进行研究。对第一个问题的分析 三年的随访显示，每种疫苗的成功率约为50%。 在寻求治疗的患者中发现预防霍乱发作的措施 在医疗机构。期间进行的分析的具体目标 过去一年包括：1)评估#年疫苗的效力 第四年和第五年的后续行动；2)评估是否 预防霍乱弧菌01无症状感染的疫苗 以及引起腹泻的感染太轻而不值得征集 医疗保健；以及3)分析霍乱发病率和 死亡与参与试验本身有关。 这些分析表明：1)没有明显的保护措施 在第四和第五年的后续行动中治疗霍乱；2) 在第一年的跟踪期间，当积极监测允许的时候 抗霍乱弧菌01感染的比较疗效评价 在所有严重程度中，两种疫苗都提供了约30%的保护 防止无症状感染，BS-WC(但不保护WC)都有保护 对抗霍乱弧菌01腹泻，并改变了 从较严重的疾病到较轻的疾病的发作； 试验目标年龄-性别组中的非参与者展示了 霍乱发病率和死亡率都比参与者高出约30% 服用了安慰剂的人。 来年的进一步分析将探讨以下方面的影响 疫苗评估的效力与效力视角 保护以及涉及V.V.流行病学的其他专题。 这里的霍乱弧菌。

This project entails continuing analyses of data derived from a large- scale, placebo-controlled field trial of B subunit-killed whole cell (BS-WC) and killed whole cell-only (WC) oral vaccines against cholera, conducted between 1985-90 in the Matlab field studies area of the International Center for Diarrheal Disease Research, Bangladesh. The trial enrolled ca. 89,000 subjects for study. Analyses of the first three years of follow-up revealed that each vaccine conferred ca. 50% protection against cholera episodes detected among patients seeking care at medical facilities. Specific goals of analyses conducted during the past year included: 1) evaluation of the efficacy of the vaccines during the fourth and fifth years of follow-up; 2) assessment of whether each vaccine protected against asymptomatic infections by V. cholerae 01, as well as infections causing diarrhea too mild to warrant solicitation of medical care; and 3) analyses of whether the incidence of cholera and death were correlated with participation in the trial per se. These analyses demonstrated that: 1) no protection was evident against treated cholera during the fourth and fifth years of follow-up; 2) during the first year of follow-up, when active surveillance permitted assessment of the comparative efficacy against V. cholerae 01 infections of all grades of severity, both vaccines conferred ca. 3O% protection against asymptomatic infections, and BS-WC (but not WC) both protected against V. cholerae 01 diarrhea and shifted the spectrum of such episodes from more severe to less severe disease; and 3) non-participants in the age-sex groups targeted for the trial exhibited a ca. 3O% higher incidence of both cholera and death than participants who ingested the placebo. Further analyses during the coming year will explore the implications of efficacy vs. effectiveness perspectives for estimates of vaccine protection, as well as other topics addressing the epidemiology of V. cholerae in this setting.