Key populations or key populations at higher risk.

 Key populations, or key populations at higher risk, are groups of people who are more likely to be exposed to HIV or transmit it and whose engagement is critically important for a successful HIV response. In all countries, key populations include people living with HIV. In most settings, men who have sex with men, transgender people, people who inject drugs and sex workers and their clients are at higher risk of exposure to HIV than other groups. However, each country should define the specific populations that are key to their epidemic and response based on the epidemiological and social context.

UNAIDS considers gay men and other men who have sex with men, sex workers and their clients, transgender people and people who inject drugs as the four main key population groups. These populations often suffer from punitive laws or stigmatizing policies, and they are among the most likely to be exposed to HIV. Their engagement is critical to a successful HIV response everywhere—they are key to the epidemic and key to the response. Countries should define the specific populations that are key to their epidemic and response based on the epidemiological and social context. The term “key populations” is also used by some agencies to refer to populations other than the four listed above. For example, prisoners and other incarcerated people also are particularly vulnerable to HIV; they frequently lack adequate access to services, and some agencies may refer to them as a key population. The term key populations at higher risk alsomay be used more broadly, referring to additional populations that are most at risk of acquiring or transmitting HIV, regardless of the legal and policy environment. In addition to the four main key populations, this term includes people living with HIV, seronegative partners in serodiscordant couples and other specific populations that might be relevant in particular regions (such as young women in southern Africa, fishermen and women around some African lakes, long-distance truck drivers and mobile populations).

In addition, UNAIDS also uses the term priority populations to describe groups of people who in a specific geographical context (country or location) are important for the HIV response because they are at increased risk of acquiring HIV or disadvantaged when living with HIV, due to a range of societal, structural or personal circumstances. In addition to people living with HIV and the globally defined key populations that are important in all settings, countries may identify other priority populations for their national responses, if there is clear local evidence for increased risk of acquiring HIV, dying from AIDS or experiencing other negative HIV related health outcomes among other populations. In line with the country epidemiology of HIV, associated factors and inequalities, this may include populations such as adolescent girls, young women and their male partners in locations with high HIV incidence, sexual partners of key populations, people on the move, people with disabilities, indigenous peoples, mine workers, as well as others in specific countries. However, in the vast majority of settings, key populations and people living with HIV are the most important priority populations for achieving global targets. Source: UNAIDS Terminology guidelines 2015. Geneva: UNAIDS; 2015. Available at