Estimation of vaccine efficacy in the presence of waning: application to cholera vaccines.
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.
Durham
L K
LK
Department of Biostatistics, The Rollins School of Public Health, Emory University, Atlanta, GA 30322, USA.
Longini
I M
IM
Halloran
M E
ME
Clemens
J D
JD
Nizam
A
A
Rao
M
M
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
D022121:Cholera Vaccines