Disease scenarios and rules of disease dynamics.

Four clinical states and 16 transition probabilities between states are represented (using Markov chains). Population-level transition probabilities are represented in the 4–4 matrix T (i.e with 4 rows and 4 columns, upper right). The transition probabilities are denoted by pij and pii, where pij is the probability of moving from state i to state j and pii is the probability to stay in this state i. Numerical values for transition probabilities are given in Table 1. According to international nomenclature of stochastic matrix, the row vector of the Markov chains has been written in order to meet the following criteria: non negative coefficients and the sum of each row equal to 1.