Estimating the size of populations at risk for HIV
Issues and methods, updated July 2003
UNAIDS/WHO working group on HIV/AIDS/STI surveillance
The difficulty in focusing prevention efforts appropriately is especially pronounced in countries where HIV remains largely concentrated among sub-populations whose behaviour puts them at high risk for contracting and transmitting HIV. Many governments find it politically difficult to invest in services for injecting drug users, men who have sex men and female sex workers and the clients they serve. And yet in most countries in the world outside of sub-Saharan Africa, these sub-populations remain among the most important focal points for effective HIV prevention.