title: Estimating the size of key populations at higher risk of HIV infection: a summary of experiences and lessons presented during a technical meeting on size estimation among key populations in Asian countries.
abstract: OBJECTIVE
  Size estimates of key populations at higher risk of HIV exposure are recognized as critical for understanding the trajectory of the HIV epidemic and planning and monitoring an effective response, especially for countries with concentrated and low epidemics such as those in Asia.
  
  
  BACKGROUND
  To help countries estimate population sizes of key populations, global guidelines were updated in 2011 to reflect new technical developments and recent field experiences in applying these methods.
  
  
  METHODS
  In September 2013, a meeting of programme managers and experts experienced with population size estimates (PSE) for key populations was held for 13 Asian countries. This article summarizes the key results presented, shares practical lessons learnt and reviews the methodological approaches from implementing PSE in 13 countries.
  
  
  CONCLUSIONS
  It is important to build capacity to collect, analyse and use PSE data; establish a technical review group; and implement a transparent, well documented process. Countries should adapt global PSE guidelines and maintain operational definitions that are more relevant and useable for country programmes. Development of methods for non-venue-based key populations requires more investment and collaborative efforts between countries and among partners.
authors.affiliation: HIV, Hepatitis and STI, World Health Organization Regional Office for the Western Pacific, Manila, Philippines .
authors.forename: Dongbao
authors.initials: D
authors.lastname: Yu
authors.affiliation: HIV Department, World Health Organization, Geneva, Switzerland .
authors.forename: Jesus Maria Garcia
authors.initials: JM
authors.lastname: Calleja
authors.affiliation: The Global Fund to fight AIDS, Tuberculosis and Malaria, Geneva, Switzerland .
authors.forename: Jinkou
authors.initials: J
authors.lastname: Zhao
authors.affiliation: Joint United Nations Programme on HIV/AIDS, Regional Support Team for Asia and the Pacific, Bangkok, Thailand .
authors.forename: Amala
authors.initials: A
authors.lastname: Reddy
authors.affiliation: World Health Organization Representative Office in China, Beijing, China .
authors.forename: Nicole
authors.initials: N
authors.lastname: Seguy
mesh_terms: D001208:Asia / Q000453:epidemiology; D003226:Congresses as Topic; D058872:Epidemics; D005260:Female; D006678:HIV; D015658:HIV Infections / Q000453:epidemiology* / Q000209:etiology; D006801:Humans; D008297:Male; D011156:Population Density; D044382:Population Groups; D012307:Risk Factors; D060386:Sex Workers; D012747:Sexual Partners; D015819:Substance Abuse, Intravenous / Q000821:virology; D035862:Vulnerable Populations