In 2005, an estimated 2.5 million people in India had HIV/AIDS, making it one of the most highly infected countries in the world. In response, the Indian Government planned to introduce new strategies to control and prevent the spread of the disease. With the nature of the epidemic changing, moving from high risk groups to the general population and from urban to rural areas, two government clinical doctors, Dr Kurapati Sudhakar and Dr Thomas Kurien, realised they needed more help.

They asked Dr Arni S.R. Srinivasa Rao (then a Fellow at the Indian Institute of Science and a visitor at the Mathematical Institute, Oxford), to model the effectiveness of different interventions to reverse the spread of the disease. He had first caught their eye back in 2002, after publishing his PhD analysing the number of AIDS-related deaths in India,

Dr Rao asked Prof Philip Maini, a former collaborator, and Professor of Mathematical Biology at Oxford University, to work with him. Over eight months, they combined Professor Maini’s modelling expertise with Dr Rao’s deep understanding of the key population groups. They analysed many complex factors, including a novel feature incorporating the effects of preventive measures (such as anti-retroviral therapy) on people already infected with HIV/AIDS.

Mathematical modelling had not previously been used in this way in Indian health policy, and applying it within epidemiology and global development was relatively new territory for both researchers. However, as Professor Maini told us: “The subject does not matter too much. The role of the modeller is to make sure maths is embedded in science.”


The two government doctors, Dr Sudhakar and Dr Kurien, were able to ensure that the findings from the models were utilised in policy. The model’s predictions indicated that there would be a reduction in HIV/AIDS cases if the the Indian Government continued with it’s strategies. This strengthened the case for the continued implementation of government policies. The models also proved to be incredibly accurate. By 2011 the number of people living with HIV/AIDS in India had reduced to below 2.09 million, just 0.5% away from the model’s predictions. The work was also published in an academic journal and used as a REF case study.

Dr. Rao was happy to be able to contribute something to society and has since become a strong advocate for mathematical modelling, with both Dr Rao and Professor Maini continuing to provide crucial input to India’s HIV/AIDS policies. Dr Rao has also used modelling to study the spread of bird and swine flu in India.

Lessons, challenges and learning

The two Government doctors were highly influential in taking the findings to the national and district level of government, and in recognising the need for maths. Prof.Phillip Maini explains, “The reason why we had impact is that two colleagues saw the potential impact of mathematical modelling. When non-mathematicians see the potential of maths is when you have impact. It doesn’t work if mathematicians initiate or insist.” 

The interdisciplinary collaboration and existing working relationship was key for impact, utilising Professor Maini’s expertise in the field of mathematical modelling and Dr.Rao’s knowledge of key diseased groups. Professor Maini is now training and inspiring a new generation of modellers by seating biologists and mathematicians together at the lively Wolfson Centre for Mathematical Biology at Oxford University. They are able to develop a common language and gain a recognition of the skills in both disciplines.

Case study links