Efficacy calculation in randomized trials: global or local measures?
This study tests whether the effect of a vaccine trial varies in space and why. Analytical z-score maps identify unusually high- and low-efficacy values in a trial area. Relationships between neighborhood efficacy and ecological variables are measured to explain why efficacy varies in space. Efficacy was found to vary regardless of neighborhood size and the variation is related to several ecological determinants. Local efficacy measures can help public health practitioners make better decisions about when and where to vaccinate populations. The concepts offered in this study are pertinent for any health intervention trial, not just vaccines.
Emch
Michael
M
Department of Geography, Saunders Hall, University of North Carolina, Chapel Hill, NC 27599-3220 USA. emch@email.unc.edu
Ali
Mohammad
M
Acosta
Camilo
C
Yunus
Mohammad
M
Sack
David A
DA
Clemens
John D
JD
D000293:Adolescent; D000367:Age Factors; D001459:Bangladesh / Q000453:epidemiology; D002648:Child; D002675:Child, Preschool; D002771:Cholera / Q000453:epidemiology / Q000517:prevention & control*; D022121:Cholera Vaccines / Q000008:administration & dosage*; D016000:Cluster Analysis; D004311:Double-Blind Method; D004341:Drug Evaluation / Q000379:methods*; D005260:Female; D040362:Geographic Information Systems; D006801:Humans; D032521:Immunity, Herd; D017589:Immunization Programs; D008297:Male; D011159:Population Surveillance; D016032:Randomized Controlled Trials as Topic; D012111:Residence Characteristics; D016896:Treatment Outcome
D022121:Cholera Vaccines