Nonparametric estimation of survival function of HIV+ patients with doubly censored data.

In the analysis of follow-up studies of patients who have been or may be infected by the Type-1 human immunodeficiency virus (HIV-1), which causes the acquired immune deficiency syndrome (AIDS), one problem of interest is the estimation of distribution of the survival function when the origin and end points defining the survival time suffer interval censoring. In this paper, we have compared Kaplan-Meier, midpoint estimation and sun (1997), by analysis of a cohort study data of Iranian Injecting Drug Users (IDU) who became HIV infected through the using common infected syringe.