Grant: Doctoral Research Award - PA: Health Services/Pop. Health HIV/AIDS Research

Pakistan has substantial heterogeneity in HIV prevalence and risk behaviors across different geographic areas and high risk populations. HIV prevalence has reached 50% among injection drug users in some areas and is recently beginning to appear among sex workers - large populations representing significant potential for transmission to the general population. Little is understood about the diversity and trajectory of HIV epidemics in Pakistan. This project will investigate and characterize HIV transmission chains in Pakistan using molecular, behavioural and social network data. By sequencing particular genes isolated from HIV specimens of a sample of infected individuals and grouping them according to sequence similarities, clusters of closely related HIV strains can be identified. Clusters represent specimens that share a common ancestor and therefore are part of the same transmission chain (subepidemic). Clusters may differ a lot in terms of trajectory, population membership and size, behaviours and geographic location and may therefore require unique HIV prevention program configurations in optimal locations targeting that specific transmission chain. Cluster features also reveal the success of interventions, as large clusters suggest that transmission has not been abated. Transmission routes may be further described using network data, which indicates sexual and injection bridging between individuals. I propose to perform molecular analysis on specimens isolated from dry blood spots from injection drug users in 2011 and 2013 and female, male, and transgender sex workers in 2011 and link these results to accompanying behavioural and geographic data. In 2013 sexual and injection network data among injection drug users will also be collected. This project will provide a uniquely comprehensive understanding of the heterogeneity and population dynamics of HIV subepidemics in Pakistan, which will be critical to strategically design targeted HIV prevention programs.