Grant: Operating Grant

Persons who inject drugs are at much greater risk of acquiring HIV than the general population. HIV prevalence has reached 50% among persons who inject drugs. In many countries, HIV epidemics in these populations spill over into other groups at higher risk such as sex workers, thereby greatly increasing the overall burden of HIV. Little is understood about why HIV epidemics in these populations at high risk are so diverse, with some expanding rapidly and others staying at a low level. This project will investigate reasons for this observed heterogeneity of HIV prevalence in six different cities in Pakistan, using studies of injecting behaviours and laboratory studies to see how how the HIV virus is spreading in networks of persons injecting drugs, and from those networks to sex worker populations. The study will also use mathematical models to simulate epidemics using the behavioural and molecular data to study why some epidemics expand faster than others. The study will also assess how important injecting drugs are in the overall spread of HIV in different cities, in comparison to spread through sexual routes. This project will provide a uniquely comprehensive understanding of the HIV epidemics in Pakistan, helping public health program planners to design effective HIV prevention programs for key populations in Pakistan. This information will also be valuable to understand Canada's HIV epidemic, which is also largely concentrated in key populations at greater risk for HIV, including persons who inject drugs and sex workers.