{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,9,24]],"date-time":"2026-09-24T18:19:36Z","timestamp":1790273976635,"version":"4.1.0"},"reference-count":22,"publisher":"BMJ","issue":"5","content-domain":{"domain":["bmj.com"],"crossmark-restriction":true},"short-container-title":["Sex Transm Infect"],"accepted":{"date-parts":[[2013,5,15]]},"published-print":{"date-parts":[[2013,8]]},"abstract":"<jats:sec><jats:title>Objectives<\/jats:title><jats:p>Size estimates of populations at higher risk for HIV infection are needed to help policy makers understand the scope of the epidemic and allocate appropriate resources. Population size estimates of men who have sex with men (MSM), female sex workers (FSW) and intravenous drug users (IDU) are few or non-existent in Nairobi, Kenya.<\/jats:p><\/jats:sec><jats:sec><jats:title>Methods<\/jats:title><jats:p>We integrated three population size estimation methods into a behavioural surveillance survey among MSM, FSW and IDU in Nairobi during 2010\u20132011. These methods included the multiplier method, \u2018Wisdom of the Crowds\u2019 and an approach that drew on published literature. The median of the three estimates was hypothesised to be the most plausible size estimate with the other results forming the upper and lower plausible bounds. Data were shared with community representatives and stakeholders to finalise \u2018best\u2019 point estimates and plausible bounds based on the data collected in Nairobi, a priori expectations from the global literature and stakeholder input.<\/jats:p><\/jats:sec><jats:sec><jats:title>Results<\/jats:title><jats:p>We estimate there are approximately 11\u2005042 MSM with a plausible range of 10\u2005000\u201322\u2005222, 29\u2005494 FSW with a plausible range of 10\u2005000\u201354\u2005467 FSW and approximately 6107 IDU and plausibly 5031\u201310\u2005937 IDU living in Nairobi.<\/jats:p><\/jats:sec><jats:sec><jats:title>Conclusions<\/jats:title><jats:p>We employed multiple methods and used a wide range of data sources to estimate the size of three hidden populations in Nairobi, Kenya. These estimates may be useful to advocate for and to plan, implement and evaluate HIV prevention and care programmes for MSM, FSW and IDU. Surveillance activities should consider integrating population size estimation in their protocols.<\/jats:p><\/jats:sec>","DOI":"10.1136\/sextrans-2013-051071","type":"journal-article","created":{"date-parts":[[2013,6,12]],"date-time":"2013-06-12T03:04:39Z","timestamp":1371006279000},"page":"366-371","update-policy":"https:\/\/doi.org\/10.1136\/crossmarkpolicy","source":"Crossref","is-referenced-by-count":67,"title":["Estimates of the size of key populations at risk for HIV infection: men who have sex with men, female sex workers and injecting drug users in Nairobi, Kenya"],"prefix":"10.1136","volume":"89","author":[{"given":"Jerry","family":"Okal","sequence":"first","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Scott","family":"Geibel","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Nicolas","family":"Muraguri","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Helgar","family":"Musyoki","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Waimar","family":"Tun","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Dita","family":"Broz","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"David","family":"Kuria","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Andrea","family":"Kim","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Tom","family":"Oluoch","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"H Fisher","family":"Raymond","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"239","published-online":{"date-parts":[[2013,6,11]]},"reference":[{"key":"2024051410103740000_89.5.366.1","doi-asserted-by":"publisher","DOI":"10.1097\/00002030-200411190-00010"},{"key":"2024051410103740000_89.5.366.2","doi-asserted-by":"publisher","DOI":"10.1371\/journal.pmed.0040339"},{"issue":"Suppl 3","key":"2024051410103740000_89.5.366.3","doi-asserted-by":"crossref","first-page":"S33","DOI":"10.1097\/00002030-200104003-00005","article-title":"HIV surveillance among female sex workers","volume":"15","author":"Ghys","year":"2001","journal-title":"AIDS"},{"key":"2024051410103740000_89.5.366.4","unstructured":"The U.S. President's Emergency Plan for AIDS Relief (PEPFAR). 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Guidelines on surveillance among populations most at risk for HIV. 2011. http:\/\/whqlibdoc.who.int\/publications\/2011\/9789241501668_eng.pdf (accessed 9 Jul 2012)."},{"key":"2024051410103740000_89.5.366.16","unstructured":"Geibel S Okal J Tun W . HIV and STI Prevalence among men who have sex with men in Nairobi: results from a respondent-driven sampling study. NACC First National Biennial HIV and AIDS Conference ; Nairobi, Kenya, 20 May 2011. [Abstract no D028]."},{"key":"2024051410103740000_89.5.366.17","doi-asserted-by":"publisher","DOI":"10.1111\/j.1467-9531.2007.00188.x"},{"key":"2024051410103740000_89.5.366.18","unstructured":"Kenya National Bureau of Statistics, ICF Macro. 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