Objective To determine adherence to and effectiveness of ART in adolescents versus adults in southern Africa Design Observational cohort study Setting Aid for AIDS, a private-sector disease-management program in southern Africa Subjects Adolescents (age 11–19 years; n=154) and adults (n=7,622) initiating ART between 1999 and 2006 and having a viral-load measurement within one year after ART initiation Main Outcome Measures Primary: virologic suppression (HIV viral load ≤400 copies/mL), viral rebound and CD4+ T-cell count at 6, 12, 18, 24 months after ART initiation. Secondary: adherence assessed by pharmacy refills at 6, 12 and 24 months. Multivariate analyses: log-linear regression and Cox proportional hazards. Results A significantly smaller proportion of adolescents achieved 100% adherence at each time point (adolescents: 20.7% at 6 months, 14.3% at 12 months, 6.6% at 24 months; adults: 40.5%, 27.9%, and 20.6% at each time point, respectively; p<0.01). Patients achieving 100% 12-month adherence were significantly more likely to exhibit virologic suppression at 12 months, regardless of age. However, adolescents achieving virologic suppression had significantly shorter time to viral rebound (adjusted hazard ratio 2.03; 95% CI 1.31–3.13; p<0.003). Adolescents were less likely to experience long-term immunologic recovery despite initial CD4+ T-cell counts comparable to adults. Conclusions Compared to adults, adolescents in southern Africa are less adherent to ART and have lower rates of virologic suppression and immunologic recovery and a higher rate of virologic rebound after initial suppression. Studies must determine specific barriers to adherence in this population and develop appropriate interventions.

When a drop impacts on a deep pool at moderate velocity it forms a hemispheric crater which subsequently rebounds to the original free-surface level, often forming Worthington jets, which rise vertically out of the crater centre. Under certain impact conditions the crater collapse forms a dimple at its bottom, which pinches off a bubble and is also known to be associated with the formation of a very fast thin jet. Herein we use two ultra-high-speed video cameras to observe simultaneously the dimple collapse and the speed of the resulting jet. The fastest fine jets are observed at speeds of approximately $50~\text{m}~\text{s}^{-1}$ and emerge when the dimple forms a cylinder which retracts without pinching off a bubble. We also identify what appears to be micro-bubbles at the bottom of this cylinder, which we propose are caused by local cavitation from extensional stress in the flow entering the jet. The radial collapse of the dimple does not follow capillary-inertial power laws nor is its bottom driven by a curvature singularity, as has been proposed in some earlier studies. The fastest jets are produced by pure inertial focusing and emerge at finite dimple size, bypassing the pinch-off singularity. These jets emerge from the liquid contained originally in the drop. Finally, we measure directly the compression of the central bubble following the pinch-off and the subsequent large volume oscillation, which occurs at frequencies slightly above the audible range at approximately 23 kHz.

High ART adherence was associated with lower mean monthly direct health care costs, particularly reduced hospitalization costs, in this South African HIV cohort.

Background Currently boosted protease inhibitor-containing regimens are the only option after first-line regimen failure available for patients in most resource-limited settings yet little is known about long-term adherence and outcomes. Methods We enrolled patients with virologic failure (VF) who initiated lopinavir/ritonavir-containing second-line ART. Medication possession ratios were calculated using pharmacy refill dates. Factors associated with 12-month second-line virologic suppression (viral load (VL) <50 copies/ul) and adherence were determined. Results 136 patients (median CD4 count and VL at failure: 153 cells/uL and 28,548 copies/ml, respectively) were enrolled. Adherence improved after second-line ART switch (median adherence 6 months prior, 67%; median adherence during initial 6 months of second-line ART, 100%; P=0.001). Higher levels of adherence during second-line ART was associated with month 12 virologic suppression (OR 2.5 per 10% adherence increase, 95% CI 1.3 – 4.8, P=0.01). Time to virologic suppression was most rapid among patients with 91-100% adherence compared to patients with 80-90% and <80% adherence (log rank test, P=0.01). VF during 24 months of second-line ART was moderate (month 12, 25%, n=32/126; month 18, 21%, n=23/112; month 24, 25%, n=25/99). Conclusions The switch to second-line ART in South Africa was associated with an improvement in adherence, however a moderate ongoing rate of virologic failure – among approximately 25% of patients receiving second-line ART patients at each follow-up interval – was a cause for concern. Adherence level was associated with second-line ART virologic outcome, helping explain why some patients achieved virologic suppression after switch and others did not.