Table 2. Summary of included studies.

First author, year	Location	Study design1	Sampling strategy2	Target population	HIV+ adolescents/ youth
Ankunda 2011 [77]; Ankunda 2016 [50]	Uganda	CS	FP; TR	15–24 year old HIV+	n = 425 (2011) n = 335 (2016)
Bakeera-Kitaka 2008 [58]	Uganda	CS	FP; PS	15–24 year old HIV+	n = 75
Banura 2008 [57]	Uganda	CS	FP; CS	12–24 year old HIV+ and HIV-	n = 82
Baryamutuma 2010 [59]	Uganda	CS	FP; CS	13–19 year old HIV+	n = 386
Beyeza-Kasheysa 2011 [60]	Uganda	CS (PCS)	FP; CS	15–24 year old HIV+ & HIV-	n = 276 (2009) n = 206 (2011)
Birungi 2009 [51]; Birungi 2009 [74]; Obare 2010 [118]	Uganda	CS	FP-CP; CS	15–19 year old HIV+ and status unknown)	n = 732
Birungi 2011 [61]	Kenya	CS	FP; PS	15–19 year old HIV+ females	n = 757
Cataldo 2012 [28]	Malawi, Mozambique, Zambia, Zimbabwe	CS	NR; CS	10–19 year old HIV+	n = 1,703
Gavin 2006 [68]	Zimbabwe	CS	CRS; TR	15–19 year old	n = 192
Gray 1998 [69]	Uganda	CS (RCT)	CRS; TR	15–49 year old females	n = 361
Heffron 2010 [70]	Eastern Africa: Kenya, Rwanda, Tanzania, Uganda Southern Africa: Botswana, South Africa, Zambia	CS	CRS; TR	18–45 year old females	n = 523
Hendriksen 2007 [71]; Steffenson 2011 [83]	South Africa	CS	CRS; TR	15–24 year old	n = 1,235 (2007); n = 1,091 (2011)
Hoffman 2008 [62]	Malawi	CS (PCS)	FP; PS	18+ year old HIV+ females	n = 90
Holub 2010 [63]	Democratic Republic of Congo	CS	FP; PS	14–24 year old HIV+	n = 103
Kaggwa 2012 [125]	Uganda	CS	FP; NR	16–24 year old HIV+	n = 453
Katusiime 2012 [56]	Uganda	CS	FP; PS	15–24 year old HIV+	n = 148
Kembo 2012 [72]	Zimbabwe	CS	CRS; NR	15–24 year old HIV+ and HIV-	n = 477
Lightfoot 2007 [41]	Uganda	RCT	CNR; CS	14–21 year old HIV+	n = 100
Malaju 2013 [67]	Ethiopia	CS	FP; NR	15–24 year old HIV+ and HIV-	n = 104
Mbalinda 2015 [52]; Mbalinda 2015 [114]	Uganda	CS	FP-FRS; PS	10–19 year old HIV+	n = 624
Mhalu 2013 [76]	Tanzania	CS	FRS; TR	15–24 year old HIV+	n = 232
Morris 2012 [31]	Cameroon	CS	FRS-CP; TR	12–26 year old HIV+, HIV-, status unknown	n = 114
Muyindike 2012 [65]	Uganda	CS	FP; NR	18–49 year old women (n = 826)	n = 211
Nhamo 2013 [87]; Nhamo 2014 [78]	Zimbabwe	RCT	NR; NR	16–19 year old HIV+	n = 710
Nöstlinger 2015 [55]	Uganda	CS (PCS)	FC-CC; PS	13–17 year old HIV+	N = 532
Obare 2010 [53]	Kenya	CS	FP; PS	15–19 year old HIV+	n = 606
Pascoe 2015 [73]	Zimbabwe	CS	CRS; TR	18–22 year old HIV+ and HIV-	n = 199
Santelli 2013 [32]	Uganda	CS (PCS)	CRS; TR	15–24 year old HIV+ and HIV-	n = 204
Senyonyi 2012 [42]	Uganda	RCT	FP; CS	12–18 year old HIV+	n = 115
Shisana 2014 [29]	South African	CS	CRS; TR	All ages HIV+ and HIV-	n = 443
Snyder 2014 [40]	South Africa	PPT	FC-CC; CS	16–24 year old HIV+	n = 65
Test 2012 [75]	Rwanda	CS	FC-CC; CS	16–24 year old HIV+	n = 107
Toska 2015 [54]	South Africa	CS	FRS-CP; TR	10–19 year old HIV+	n = 858
Viegas 2015 [47]	Mozambique	CS	FC; PS	18–24 year old HIV+ and HIV-	n = 85
Wanyenze 2011 [66]	Uganda	CS	FP; CS	15–49 year old HIV+	n = 159

¹ CS cross-sectional study, PCS prospective cohort survey, PPT pre and post-test; RCT randomised controlled trial.

² Sampling strategy documented at two levels: (1) cluster: facility random and/ or stratified (FRS); facility purposeful (FP), community random and/or stratified (CRS), community purposeful (CP), mixed–see symbols (2) individual: total/ random (TR), purposeful (PS), convenience (CS); NR–not reported.