[Application of cluster randomization method on typhoid Vi vaccine trails].
OBJECTIVE
To describe the design and application of cluster randomized controlled method on typhoid Vi vaccine trial, and to assess the effect of implementation.


METHODS
Simple size calculation of cluster-randomized trial was used to determine the sample size of the two groups and a vaccination campaign was conducted. The study group was given typhoid Vi vaccine and the control group was given meningococcal A vaccine.


RESULTS
According to sample size calculation, a total sample of 96,121 participants was required and the study areas were divided into 108 clusters. In practice, 53 study clusters with 44,054 participants and 54 control clusters with 48,422 participants were stratified and matched according to size, location (urban or rural), characteristics (school, department, factory, demography) were randomized respectively. Confounding factors of two groups including age, sex, resident area, income, level of education were compared. It was found that the ratio of all confounding factors between the two groups were comparable and balanced.


CONCLUSIONS
Confounding factors can be better controlled between study group and the control group by applying cluster-randomized method on vaccine trail which enabled the intervention to be more scientifically evaluated; The implementation of cluster randomization trial was simple and easy to be accepted.
Dong
Bai-qing
BQ
Guangxi Center for Disease Prevention and Control, Nanning 530021, China.
Yang
Jin
J
Tang
Zhen-zhu
ZZ
Yang
Hong-hui
HH
Zeng
Jun
J
Zhang
Jie
J
Wang
Ming-liu
ML
Liang
Gui-chen
GC
Si
Guo-ai
GA
Li
Cui-yun
CY
Liang
Da-bin
DB
Liao
He-zhuang
HZ
Ochiai
Rion Leon
RL
Mohammad
Ali
A
Acosta
Camilo J
CJ
Clemens
John
J
D000293:Adolescent; D000328:Adult; D002648:Child; D002675:Child, Preschool; D002681:China; D016000:Cluster Analysis; D005260:Female; D006801:Humans; D008297:Male; D032541:Mass Vaccination / Q000458:organization & administration*; D008875:Middle Aged; D011135:Polysaccharides, Bacterial / Q000276:immunology*; D014435:Typhoid Fever / Q000517:prevention & control*; D014436:Typhoid-Paratyphoid Vaccines / Q000276:immunology*; D014611:Vaccination
D011135:Polysaccharides, Bacterial; D014436:Typhoid-Paratyphoid Vaccines; C057664:Vi polysaccharide vaccine, typhoid