On Estimating the Time from HIV Infection to AIDS - A Stochastic Modeling Approach

Objectives: To construct a statistical model through which one can estimate the mean time to get AIDS condition in a HIV infected individual. Methods: The methodology adopted for the construction of the statistical model for estimating the time to get AIDS condition considers the antigenic diversity threshold and the antigenic diversity induced by the virus entered through every individual infected sexual contact and the antigenic diversity induced by their corresponding quasi – species. A comparison has been made with the existing model in the literature which considers the antigenic diversity developed through sexual contacts only, with reference to the expected time to get AIDS and its variance. Findings: On evaluating the model constructed, it is seen that the time to get AIDS is adversely affected by the number of contacts with infected individuals and the antigenic diversity induced by the virus entered through those contacts as well as their quasi-species. It is observed that a person will attains AIDS condition sooner when the number of contacts with the infected individual increases. Novelty: Similar types of models developed to estimate the time to get AIDS condition in an infected individual consider only the number of contacts and the amount of virus transmitted. Here an additional factor of Antigenic diversity induced by the quasi-species is also considered. Keywords: Human Immunodeficiency Virus, AIDS, Viral quasi-species, Antigenic Diversity Threshold