Mother-to-child transmission of HIV: a simulation-based approach for the evaluation of intervention strategies

Abstract

Mother-to-child transmission (MTCT) of HIV is the most significant source of HIV infection in children below the age of 15 years. In 2000 alone, about 600 000 new infections occurred, the vast majority from mothers living in developing countries who were not aware of their HIV-positive status. To date, at least 4.3 million children have died from AIDS. In this paper, we discuss the development of an operational model that can be used to evaluate intervention options for the prevention of MTCT of HIV. The problem was approached by defining suitable pregnancy risk groups, prevention options and the required model outputs to evaluate different intervention strategies. The method chosen to approach the problem was a discrete-event, three-phase simulation, built in Visual Basic, with a stochastic semi-Markov structure. The developed model takes individual pregnant women through each stage of their pregnancy, labour and birth. Different intervention strategies may be modelled at any time, including short-course antiretroviral drugs and cessation of breastfeeding. The model is demonstrated with data from Botswana, which has one of the highest HIV-infection rates in the world.

Keywords:

• HIV and AIDS
• health services
• simulation
• decision support systems

Acknowledgements

This research has benefited from the expert knowledge afforded by many clinicians working within the field of MTCT of HIV. In particular, we would like to express out thanks to Dr Ratish Basu Roy, Dr Harry Harindra, Dr Anton Pozniak and Dr Will Stones. As a consequence of this valuable input, we hope that the model presented here captures realistic and up-to-date issues of the MTCT natural history, and available interventions. We are grateful for the financial support received from DfID and the Opportunities and Choices Programme.