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Title
HIV prevalence and incidence in adolescent girls and young women in Lesotho: Results from the LePHIA survey 2016-2017
Presenter
Andrea Low
Authors
A. Low1, K. Thin2, S. Davia3, J. Mantell4, M. Koto2, S. McCracken5, P. Ramphalla3, L. Maile2, N. Ahmed1, N. Fida6, A. Schwitters3, K. Frederix7
Institutions
1ICAP at Columbia University, New York, United States, 2Ministry of Health, Maseru, Lesotho, 3CDC, Maseru, Lesotho, 4Columbia University, New York, United States, 5CDC, Atlanta, United States, 6USAID, Pretoria, South Africa, 7ICAP at Columbia University, Maseru, Lesotho

Background: Adolescent girls and young women (AGYW, ages 15-24) currently account for 74% of new HIV infections in Southern Africa. A Population-based HIV Impact Assessment conducted in Lesotho (LePHIA) in 2016-2017 provides recent data on prevalence and the first assessment of national HIV incidence in AGYW.
Methods: LePHIA used a two-stage sampling design to select a nationally representative sample of adults. Individuals completed an interview and HIV testing. Incidence was measured using HIV-1 LAg avidity paired with viral load data. The association between demographic and behavioral variables and HIV prevalence and incidence was assessed using logistic regression, incorporating survey weights. A time trend in prevalence and indicators of risk was estimated using weighted data from the Demographic Health Surveys (DHS) in 2009 and 2014.
Results: Of 2708 eligible AGYW, 2358 (87%) were interviewed and tested for HIV. Weighted HIV prevalence was 11.1% (95% CI:9.7-12.5%) overall, 5.7% in 15-19 year olds (64/1156; 95% CI:4.1-7.2%) and 16.7% in 20-24 year olds (209/1202; 95% CI:14.4-19.0%). This translates into an estimated 5862 HIV-positive 15-19 year olds and 16707 20-24 year olds. Annualized incidence was high at 1.8% (95% CI:0.8-2.8%), particularly in urban areas (2.3%, 95% CI:0.7-3.9%). Since 2009, there has been a decrease in prevalence (13.6% to 11.1%), although there was an increase in 15-17 year olds (ptrend=0.02, Figure 1), possibly due to increased survival after vertical infection. Compared to 2009, there has been a two-fold increase in odds of secondary/tertiary education (Odds Ratio [OR] 2.21; 95%CI:1.90-2.56), and a 41% reduction in the odds of sexual debut before 15 years (OR 0.59, 95%CI:0.44-.79). However, there has been a significant decline in HIV knowledge (OR 0.72, 95%CI:0.60-0.86). Correlates of prevalent infection include an HIV-positive partner (adjusted OR (aOR) 11.72, 95%CI:6.07-22.62, Table 1), anal sex history (aOR 3.08, 95%CI:1.11-8.57), and having lived outside Lesotho for >1month in past year (aOR 1.82, 95%CI:1.01-3.31). For the 642 AGYW living with parents, maternal education was strongly protective, even after adjusting for household wealth.
Conclusions: HIV prevalence is declining in AGYW, but incidence remains high. Indicators of risk are improving, aside from HIV knowledge, which conveys risk for future acquisition.


Figure 1. Weighted prevalence in adolescent girls and young women in Lesotho, 2009-2017
[Figure 1. Weighted prevalence in adolescent girls and young women in Lesotho, 2009-2017]




CharacteristicOdds Ratio (95% CI)Adjusted Odds Ratio (95% CI)p-values (determined by logistic regression)
Rural residence0.61 (0.46-0.80)0.60 (0.40-0.90)0.01
Never left Lesotho Away for >1 month in lifetime Away for >1 month in past year1 1.23 (0.76-2.00) 2.54 (1.56-4.14)1 1.36 (0.68-2.72) 1.82 (1.01-3.31)0.37 0.05
Education None Primary Secondary Tertiary/ Above Secondary1 0.41 (0.13-1.32) 0.28 (0.09-0.88) 0.20 (0.06-0.67)1 0.29 (0.06-1.36) 0.22 (0.05-1.01) 0.09 (0.02-0.42)0.11 0.05 0.04
Number of lifetime sexual partners One 2 to 3 ≥41 2.16 (1.51-3.10) 3.93 (2.43-6.36)1 1.84 (1.21-2.78) 2.44 (1.45-4.08)0.006 0.002
Ever had anal sex3.17 (1.29-7.78)3.08 (1.11-8.57)0.03
HIV status of sexual partners in the past 12 months All HIV-negative partners Any HIV-positive partners Any partner with unknown status1 13.30 (7.89-22.43) 1.11 (0.77-1.61)1 11.72 (6.07-22.62) 1.29 (0.86-1.93)<0.001 0.21
Marital status Single Married or living with partner Divorced, separated or widowed1 2.35 (1.79-3.09) 5.43 (3.07-9.61)1 1.09 (0.62-1.93) 1.56 (0.68-3.56)0.75 0.28
Maternal education None Primary Secondary Tertiary/ Above secondary1 0.65 (0.18-2.43) 0.33 (0.08-1.42) 0.14 (0.02-1.00)1 0.16 (0.03-0.88) 0.06 (0.01-0.50) 0.03 (0.01-0.62)0.04 0.01 0.03
Highest wealth quintile0.81 (0.36-1.83)0.24 (0.05-1.33)0.10
[Table 1. Correlates of HIV infection in young women and girls in Lesotho 2017]

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