title: Estimation of vaccine efficacy in the presence of waning: application to cholera vaccines.
abstract: The authors present a nonparametric method for estimating vaccine efficacy as a smooth function of time from vaccine trials. Use of the method requires a minimum of assumptions. Estimation is based on the smoothed case hazard rate ratio comparing the vaccinated with the unvaccinated. The estimation procedure allows investigators to assess time-varying changes in vaccine-induced protection, such as those produced by waning and boosting. The authors use the method to reanalyze data from a vaccine trial of two cholera vaccines in rural Bangladesh. This analysis reveals the differential protection and waning effects for the vaccines as a function of biotype and age.
authors.affiliation: Department of Biostatistics, The Rollins School of Public Health, Emory University, Atlanta, GA 30322, USA.
authors.forename: L K
authors.initials: LK
authors.lastname: Durham
authors.forename: I M
authors.initials: IM
authors.lastname: Longini
authors.forename: M E
authors.initials: ME
authors.lastname: Halloran
authors.forename: J D
authors.initials: JD
authors.lastname: Clemens
authors.forename: A
authors.initials: A
authors.lastname: Nizam
authors.forename: M
authors.initials: M
authors.lastname: Rao
mesh_terms: D000293:Adolescent; D001459:Bangladesh / Q000453:epidemiology; D016022:Case-Control Studies; D002648:Child; D002675:Child, Preschool; D002771:Cholera / Q000453:epidemiology* / Q000517:prevention & control*; D022121:Cholera Vaccines / Q000008:administration & dosage*; D004311:Double-Blind Method; D004812:Epidemiologic Methods; D005260:Female; D006801:Humans; D007115:Immunization Schedule; D015994:Incidence; D008297:Male; D015233:Models, Statistical; D011897:Random Allocation; D012044:Regression Analysis; D012621:Seasons; D018709:Statistics, Nonparametric; D016019:Survival Analysis
chemical_list: D022121:Cholera Vaccines