Design of field studies on vaccines which involves capturing indirect effect

VernacularTitle:考虑间接效应估计的疫苗现场试验设计
Author: Jin-Ren PAN ¹ ; Zheng-Qiang HUANG ; Kun CHEN
Author Information

1. 浙江大学医学院
Keywords: Vaccine field studies; Protective effect; Indirect effect; Cluster randomization trails
From: Chinese Journal of Epidemiology 2011;32(2):182-186
CountryChina
Language:Chinese
Abstract: For most variety of vaccines, two types of effects-direct and indirect, can result from immunization programs. Unimmunized individuals in the population that receive immunization program can benefit from the vaccines in addition to the protection from immunization.The classical vaccine trails allocate individuals into study and control arms with individual randomization, so the programs' cost-benefit is underestimated due to the impossible measurement on indirect effect. The objectives of the present work are to introduce the conceptual framework,developed by Halloran et al, for four types of study designs that differentiate and account for direct,indirect, total and overall effects of intervention programs, and to explain the relationships of these effects as well. With the examples of field trails of oral cholera vaccines in Bangladesh and Vi typhoid vaccine in India, further issues refer to the identification of indirect effect. The application in practice is also discussed.