A Markov model for a clinical episode of recurrent genital herpes

A time-homogeneous Markov process is proposed for modeling the clinical course of recurrent genital herpes and is used to obtain estimators for various characteristics of the disease episode. The model has a finite, discrete time parameter and discrete state space, with six transient states corresponding to the six stages a herpes lesion may enter. The healed condition is represented as an absorbing state. The number of lesions present at the onset of the clinical episode and the number of lesions appearing during the course of the episode are assumed to have negative binomial distributions. Clinical trial data are used to examine the assumptions of the model and to estimate its parameters. Estimates of clinical variables based on the model are computed and are compared with those calculated directly to assess how well the model represents the biological process of the disease.