Background: Children perinatally-infected with HIV surviving due to pediatric ART are now ageing into adolescence. Yet monitoring adolescent treatment programs remains difficult as large, well-defined cohorts are rare. We quantify the size adolescent ART population and proportion virologic suppressed using a national patient cohort developed from South Africa''s National Health Laboratory Service (NHLS) database.
Methods: Using NHLS data on all public sector viral load tests nationally since 2004, we analyzed information on all patients aged < 20 years at test date. We estimated the total number of patients accessing ART care in a given year as the number of individual patients with viral load results. Data were stratified by age and year (2004-2014) to assess shifts in age distribution on ART over time. We also assessed proportions virally suppressed in 2014, by age.
Results: A total of 929,274 person-years were analysed. There was a steady increase in number of children on ART under 5-years from 2004-2011, after which numbers stabilized, likely due to PMTCT successes. There were large increases in numbers of adolescents on ART, rising 10- to 20-fold from 2004-2007 to 2012-2014. Further increases are expected in 15-19 year-olds for the next decade, after which the younger cohort ageing into adolescence will decline. In 2014, the proportion virally suppressed was 71% among 5-9y (95%CI 71-72%), 65% among 10-14y (95%CI 65-66%), and 61% among 15-19y (95%CI 60-61%).
Conclusions: The rollout of PMTCT and pediatric ART led to a demographic bulge of HIV-infected adolescents and subsequently large numbers of adolescents receiving ART. Declining viral suppression among older adolescence suggests an urgent need to improve care for this vulnerable and growing population. Laboratory datasets represent an important tool for national and local resource planning and allocation.

 0-1 years1-4 years5-9 years10-14 years15-19 Years
2004-200711,593 (15%)27,157 (35%)24,921 (32%)8,854 (11%)5,904 (8%)
2008-201129,983 (9%)88,391 (26%)110,737 (33%)72,774 (22%)34,981 (10%)
2012-201431,299 (6%)89,530 (17%)155,163 (30%)141,945 (28%)96,042 (19%)
[Table1: Distribution of viral load test results by age category and calendar year]

Figure 1: Distribution of individual viral load test results by age and period
[Figure 1: Distribution of individual viral load test results by age and period]