Nonparametric survival analysis and vaccine efficacy using   Dempster-Shafer analysis
  We introduce an extension of nonparametric DS inference for arbitrary univariate CDFs to the case in which some failure times are (right)-censored, and then apply this to the problem of assessing evidence regarding assertions about relative risks across two populations. The approach enables exploration of the sensitivity of survival analyses to assumed independence of the missing data process and the failure proces. We present an application to the partially efficacious RV144 (HIV-1) vaccine trial, and show that the strength of conclusions of vaccine efficacy depend on assumptions about the maximum failure rates of the subjects lost-to-followup. 
Paul T. Edlefsen and Arthur P. Dempster
stat.ME stat.AP