Performance of the BD FACSPresto near to patient analyzer in comparison with representative conventional CD4 instruments in Cameroon.

BACKGROUND: In the context of scaling the viral load in resource limited settings, following HIV infected patient's adults and children with CD4+ T-lymphocyte count still very important in settings where the decentralization of treatment still has some challenges. Effective HIV monitoring in these resource-constrained settings needs affordable and reliable CD4+ T lymphocytes enumeration methods. We investigated the validity of a BD FACSPresto POC which is a dedicated system for enumeration that uses immunofluorescent technologies. In this study, we have assessed the sensitivity, specificity and correlation between most representative flow cytometry instruments present in Cameroon with more than 5000 CD4 T cells tests per year including FACSCalibur, FACSCount, and PIMA POC from Becton-Dickinson and ALERE respectively. METHODS: 268 patients aged from 1 to 72 years old were enrolled and included in the study after inform consent. The BD FACSPresto POC CD4+ T cell technology was placed at CIRCB and operated by technician staff. HIV infected patients were from Chantal BIYA international reference Center (CIRCB), Centre de Sante Catholique de NKOLODOM, Centre de Sante Catholique de BIKOP and CASS de Nkolndongo-Yaounde We compared the accuracy of the BD FACSPresto and three existing reference technologies with more than 5000 tests per year like FACSCalibur, FACSCount and PIMA according to the number of CD4 test done per year and their repartition in the country. Bland-Altman method and correlation analysis were used to estimate mean bias and 95% limits of agreement and to compare the methods, including analysis by subgroup of participant gestational age. In addition sensitivity and specificity were determined. Statistical significance was set at P-value < 0.05. RESULTS: The BD FACSPresto POC system has excellent precision, accuracy and linearity for CD4+ T lymphocytes enumeration. Good correlations were obtained between the BD FACSPresto poc system and other single platform methods. Bland-Altman plots showed interchangeability between two machines mean bias BD-FACSPresto vs PIMA = - 126,522(- 161,221 to - 91,822) BD-FACSPresto vs FACSCount = - 38,708 (- 58,935 to - 18,482) and FACSPresto vs FACSCALIBUR = 0.791(- 11,908 to 13,491). Mean difference with Absolute CD4+ T-lymphocyte values obtained from the BD FACSPresto system correlated well with PIMA, FACSCount, and FACSCalibur method with R2 equal to 0.88, 0.92 and 0.968 respectively with P < 0.001 for all. The mean comparison between values obtained from BD FACSPresto with PIMA, FACSCount, and FACSCalibur using paired T test give P = 0.17, P = 0.5 and P = 0.6 respectively meaning that there is no significant differences between values obtained with BD FACSPresto and PIMA, FACSCount or FACSCalibur CD4 enumeration machines. Further analysis revealed close agreement between all the three instruments with no significant difference between the forth methods (P = 0.91). CONCLUSION: This BD-FACSPresto POC system is a simple, robust and reliable system for enumeration of absolute and percentage of CD4+ T-lymphocytes especially suitable for remote areas with limited resources. Having one BD-FACSPresto POC system easy to use, should reduce the cost and thus increase and improved access to CD4 testing for HIV infected patients in resource-constrained countries. BD-FACSPresto POC CD4 will enable reduction in patient time and improve the overall quality of ART service count and may improve test access in remote areas. This technology can allow for greater decentralization and wider access to CD4 testing and ART.

HIV-1 drug resistance testing is essential for heavily-treated patients switching from first- to second-line regimens in resource-limited settings: evidence from routine clinical practice in Cameroon.

BACKGROUND: With the phase-out of stavudine (d4T), change to first-line regimens with zidovudine (AZT) or tenofovir (TDF) in resource-limited settings (RLS) might increase risks of cross-resistance to nucleos(t) ide reverse transcriptase inhibitors (NRTI). This would restrict the scope of switching to the World Health Organisation (WHO)-recommended standard second-line combinations (SLC) without HIV drug resistance (HIVDR)-testing in routine clinical practice. METHODS: An observational study was conducted among 101 Cameroonian patients (55.4% male, median [IQR] age 34 [10-41] years) failing first-line antiretroviral therapy (ART) in 2016, and stratified into three groups according to NRTIs exposure: exposure to both thymidine analogues AZT "and" D4T (group-A, n = 55); exposure to both TDF and AZT "or" D4T (group-B, n = 22); exposure solely to D4T (group-C, n = 24). Protease-reverse transcriptase HIVDR was interpreted using the HIVdb penalty scores (≥60: high-resistance; 20-59: intermediate-resistance; < 20: susceptible). The acceptable threshold for potential-efficacy was set at 80%. RESULTS: The median [IQR] CD4, viral RNA, and time on ART, were respectively 129 [29-466] cells/µl, 71,630 [19,041-368,000] copies/ml, and 4 [2-5] years. Overall HIVDR-level was 89.11% (90/101), with 83.2% harbouring M184 V (high-level 3TC/FTC-resistance) and only 1.98% (2/101) major HIVDR-mutations to ritonavir-boosted protease-inhibitors (PI/r). Thymidine-analogue mutations (TAMs)-1 [T215FY (46.53%), M41 L (22.77%), L210 W (8.91%)], with cross-resistance to AZT and TDF, were higher compared to TAMs-2 [D67N (21.78%), K70R (19.80%), K219QE (18.81%)]. As expected, K65R was related with TDF-exposure: 0% (0/55) in group-A, 22.72% (5/22) group-B, 4.17% (1/24) group-C (p = 0.0013). The potential-efficacy of AZT vs. TDF was respectively 43.64% (24/55) vs. 70.91% (39/55) in group-A (p = 0.0038); 63.64% (14/22) vs. 68.28% (15/22) in group-B (p = 1.0000); and 37.50% (9/24) vs. 83.33% (20/24) in group-C (p = 0.0032). CRF02_AG was the prevailing subtype (63.40%), followed by CRF11.cpx (8.91%), A1 (7.92%), G (5.94%); without any significant effect of the subtype-distribution on HIVDR (92.2% in CRF02_AG vs. 83.8% in non-AG; p = 0.204). CONCLUSION: First-line ART-failure exhibits high-level NRTI-resistance, with potential lower-efficacy of AZT compared to TDF. Significantly, using our 80% efficacy-threshold, only patients without NRTI-substitution on first-line could effectively switch to SLC following the WHO-approach. Patients with multiple NRTI-substitutions (exposed to both thymidine-analogues and TDF) on first-line ART would require HIVDR-testing to select active NRTIs for SLC.

Strategic HIV Case Findings among Infants at Different Entry Points of Health Facilities in Cameroon: Optimizing the Elimination of Mother-To-Child Transmission in Low- and- Middle-Income Countries.

BACKGROUND: HIV case finding is an essential component for ending AIDS, but there is limited evidence on the effectiveness of such a strategy in the pediatric population. We sought to determine HIV positivity rates among children according to entry points in Cameroon. METHODS: A facility-based survey was conducted from January 2015 to December 2019 among mother-child couples at various entry points of health facilities in six regions of Cameroon. A questionnaire was administered to parents/guardians. Children were tested by polymerase chain reaction (PCR). Positivity rates were compared between entry points. Associations were quantified using the unadjusted positivity ratio (PR) for univariate analyses and the adjusted positivity ratio (aPR) for multiple Poisson regression analyses with 95% confidence intervals (CIs). p-values < 0.05 were considered significant. RESULTS: Overall, 24,097 children were enrolled. Among them, 75.91% were tested through the HIV prevention of mother-to-child transmission (PMTCT) program, followed by outpatient (13.27%) and immunization (6.27%) services. In total, PMTCT, immunization, and outpatient services accounted for 95.39% of children. The overall positivity was 5.71%, with significant differences (p < 0.001) between entry points. Univariate analysis showed that inpatient service (PR = 1.45; 95% CI: [1.08, 1.94]; p = 0.014), infant welfare (PR = 0.43; 95% CI: [0.28, 0.66]; p < 0.001), immunization (PR = 0.56; 95% CI: [0.45, 0.70]; p < 0.001), and PMTCT (PR = 0.41; 95% CI: [0.37, 0.46]; p < 0.001) were associated with HIV transmission. After adjusting for other covariates, only PMTCT was associated with transmission (aPR = 0.66; 95% CI: [0.51, 0.86]; p = 0.002). CONCLUSIONS: While PMTCT accounts for most tested children, high HIV positivity rates were found among children presenting at inpatient, nutrition, and outpatient services and HIV care units. Thus, systematic HIV testing should be proposed for all sick children presenting at the hospital who have escaped the PMTCT cascade.

The mother-to-child transmission of HIV-1 and profile of viral reservoirs in pediatric population: A systematic review with meta-analysis of the Cameroonian studies.

BACKGROUND: The mother-to-child transmission of HIV-1 (MTCT) remains on the major route of HIV-transmission among pediatric populations in Africa. Though a prevention of MTCT (PMTCT) high-priority country, data on the MTCT burdens in Cameroon remains fragmented. OBJECTIVE: We sought to assess the pooled MTCT rate, its risk-factors, and to characterize viral reservoirs of infected-children in Cameroon. METHODS: All relevant observational cohort and cross-sectional studies conducted in Cameroon were searched from PubMed, African Journals Online, Google scholar, ScienceDirect and academic medical education databases. Heterogeneity and publication bias were respectively assessed by the I2 statistic and the Egger/funnel plot test. Meta-analysis was performed using the random effects model. MTCT rate >5% was considered as "high". This review was registered in the Prospero database, CRD42021224497. RESULTS: We included a total of 29 studies and analyzed 46 684 children born from HIV-positive mothers. The overall rate of MTCT was 7.00% (95% CI = 6.07-8.51). According to regions, the highest burden was in Adamaoua-region (17.51% [95% CI:14.21-21.07]) with only one study found. PMTCT option-B+ resulted in about 25% reduction of MTCT (8.97% [95% CI: 8.71-9.24] without option-B+ versus 2.88% [95% CI: 5.03-9.34] with option-B+). Regarding risk-factors, MTCT was significantly associated with the absence of PMTCT-interventions both in children (OR:5.40 [95% CI: 2.58-11.27]) and mothers (OR: 3.59 [95% CI: 2.15-5.99]). Regarding viral reservoirs, a pro-viral DNA mean of 3.34±1.05 log10/mL was observed among 5/57 children and archived HIV drug resistance mutations were identified in pro-viral DNA marker among 21/79 infected-children. CONCLUSION: In spite of the dropdown in MTCT following option-B+ implementation, MTCT remains high in Cameroon, with substantial disparities across regions. Thus, in this era of option-B+, achieving MTCT elimination requires interventions in northern-Cameroon. The variation in pro-viral load in infected-children underlines the relevance of characterizing viral reservoirs for possible infection control in tropical settings.

Inflammatory profile of vertically HIV-1 infected adolescents receiving ART in Cameroon: a contribution toward optimal pediatric HIV control strategies.

Antiretroviral therapy (ART) has improved the lifespan of people living with HIV. However, their immune system remains in a state of sustained activation/inflammation, which favors viral replication and depletion of helper T-cells with varying profiles according to ART-response. We herein sought to ascertain the inflammatory profile of adolescents living with perinatal HIV-1 infection (ALPHI) receiving ART in an African context. In this cross-sectional and comparative study among ART-experienced ALPHI in Yaoundé-Cameroon, HIV-1 RNA was measured by Abbott Real-time PCR; CD4 cells were enumerated using flow cytometry; serum cytokines were measured by ELISA; HIV-1 proviral DNA was genotyped by Sanger-sequencing; and archived drug resistance mutations (ADRMs) were interpreted using Stanford HIVdb.v9.0.1. Overall, 73 adolescents were enrolled (60 ALPHI and 13 HIV-1 negative peers) aged 15 (13-18) years; 60.00% were female. ART median duration was 92 (46-123) months; median viral load was 3.99 (3.17-4.66) RNA Log10 (copies)/mL and median CD4 count was 326 (201-654) cells/mm3. As compared to HIV-negative adolescents, TNFα was highly expressed among ALPHI (p<0.01). Following a virological response, inflammatory cytokines (IFNγ and IL-12), anti-inflammatory cytokines (IL-4 and IL-10) and inflammation-related cytokines (IL-6 and IL-1ß) were highly expressed with viral suppression (VS) vs. virological failure (VF), while the chemokine CCL3 was highly expressed with VF (p<0.01). Regarding the immune response, the inflammatory cytokine TNFα was highly expressed in those that are immunocompetent (CD4≥500 cell/mm3) vs. immunocompromised (CD4<500 cell/mm3), p ≤ 0.01; while chemokine CCL2 was highly expressed in the immunocompromised (p<0.05). In the presence of ADRMs, IL-4 and CCL3 were highly expressed (p=0.027 and p=0.043 respectively). Among ART-experienced ALPHI in Cameroon, the TNFα cytokine was found to be an inflammatory marker of HIV infection; IFNγ, IL-1ß, IL-6, and IL-12 are potential immunological markers of VS and targeting these cytokines in addition to antiretroviral drugs may improve management. Moreover, CCL3 and CCL2 are possible predictors of VF and/or being immunocompromised and could serve as surrogates of poor ART response.

Characterization of the Viral Reservoirs Among HIV-1 Non-B Vertically Infected Adolescents Receiving Antiretroviral Therapy: Protocol for an Observational and Comparative Study in Cameroon.

BACKGROUND: Antiretroviral therapy (ART) can bring HIV-1 levels in blood plasma to the undetectable level and allow a near-normal life expectancy for HIV-infected individuals. Unfortunately, ART is not curative and must be taken for life, because within a few weeks of treatment cessation, HIV viremia rebounds in most patients except for rare elite or posttreatment controllers of viremia. The primary source of this rebound is the highly stable reservoir of latent yet replication-competent HIV-1 proviruses integrated into the genomic DNA of the resting memory cluster of differentiation 4 (CD4+) T cells. To achieve a cure for HIV, understanding the cell reservoir environment is of paramount importance. The size and nature of the viral reservoir might vary according to the timing of therapy, therapeutic response, ART duration, and immune response. The mechanisms of reservoir maintenance generally depend on the levels/type of immune recognition; in addition, the dynamics of viral persistence are different between pediatric and adult populations. This difference could become more evident as children grow toward adolescence. OBJECTIVE: We aim to characterize the HIV reservoirs and their variability as per the virological and immunological profiles of HIV-1 non-B vertically infected adolescents receiving ART in Cameroon during the Adolescents' Viral Reservoirs study to provide accurate and reliable data for HIV cure research. METHODS: This study will involve HIV-1 non-B vertically infected adolescents selected from an existing cohort in our institution. Blood samples will be collected for analyzing immunological/virological profiles, including CD4/CD8 count, plasma viral load, immune activation/inflammatory markers, genotyping, and quantification of HIV-1 viral reservoirs. We will equally recruit an age-matched group of HIV-negative adolescents as control for immunological profiling. RESULTS: This study received funding in November 2021 and was approved by the national institutional review board in December 2021. Sample collection will start in November 2022, and the study will last for 18 months. The HIV-1 sequences generated will provide information on the circulating HIV-1 subtypes to guide the selection of the most appropriate ART for the participants. The levels of immune biomarkers will help determine the immune profile and help identify factors driving persistent immune activation/inflammation in HIV-infected adolescents compared to those in HIV-uninfected adolescents. Analysis of the virological and immunological parameters in addition to the HIV-1 reservoir size will shed light on the characteristics of the viral reservoir in adolescents with HIV-1 non-B infection. CONCLUSIONS: Our findings will help in advancing the knowledge on HIV reservoirs, in terms of size and genetic variability in adolescents living with HIV. Such evidence will also help in understanding the effects of ART timing and duration on the size of the reservoirs among adolescents living with HIV-a unique population from whom the findings generated will largely contribute to designing functional cure strategies. INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID): PRR1-10.2196/41473.

Performance of immunochromatographic and immunoenzymatic techniques in the diagnosis of toxoplasmosis in pregnant women in Cameroon: need for harmonization.

Introduction: in order to contribute to the improvement of the management of toxoplasmosis in pregnant women in Cameroon, performance of two techniques commonly used in the diagnosis of toxoplasmosis was evaluated. Methods: a total of 541 pregnant women were recruited from seven hospitals in two Regions of Cameroon, of which 63% (341: Batch1) were from health facilities (HF) using a immunochromatographic technique (ICT) as a screening test for toxoplasmosis, and 37% (200: Batch2) from those using an immunoenzymatic technique (IEZ). On each sample, Ig (Immunoglobulin) G (IgG) and IgM were tested by three techniques: a Rapid Diagnostic Test (RDT), an Enzyme Linked Immuno Sorbent Assay (ELISA) and a Vidas Enzyme-linked fluorescent assay taken as reference (VIDAS/ELFA). The results from the health facilities were recorded. Results: for the IgG assay, our two laboratory methods were sensitive (96.0% and 97.5%) and specific (64.2% and 59.7%). Their concordance rates with the VIDAS/ELFA reference were above 60% (P<0.001). Moreover, for the IgM assay, the performances of the two methods were equivalent: Se= 18.2%, Sp= 99.4% with a low concordance rate (Kappa = 0.24). Considering the results provided by the selected hospitals, the ELISA used in Batch2 showed similar performances to the two techniques used in reference lab while the performances were low for the RDT used in Batch1. Conclusion: both methods showed similar performances (good for (IgG) and poor for IgM). However, for the immunochromatographic method, differences in performance were found between our results and those provided by the selected health facilities. These differences suggest a harmonization of diagnostic techniques for toxoplasmosis in pregnant women in Cameroonian health facilities.

Alteration of the gut fecal microbiome in children living with HIV on antiretroviral therapy in Yaounde, Cameroon.

Multiple factors, such as immune disruption, prophylactic co-trimoxazole, and antiretroviral therapy, may influence the structure and function of the gut microbiome of children infected with HIV from birth. In order to understand whether HIV infection altered gut microbiome and to relate changes in microbiome structure and function to immune status, virological response and pediatric ART regimens, we characterized the gut microbiome of 87 HIV-infected and 82 non-exposed HIV-negative children from Yaounde, a cosmopolitan city in Cameroon. We found that children living with HIV had significantly lower alpha diversity in their gut microbiome and altered beta diversity that may not be related to CD4+ T cell count or viral load. There was an increased level of Akkermansia and Faecalibacterium genera and decreased level of Escherichia and other Gamma proteobacteria in children infected with HIV, among other differences. We noted an effect of ethnicity/geography on observed gut microbiome composition and that children on ritonavir-boosted protease inhibitor (PI/r)-based ART had gut microbiome composition that diverged more from HIV-negative controls compared to those on non-nucleoside reverse-transcriptase inhibitors-based ART. Further studies investigating the role of this altered gut microbiome in increased disease susceptibility are warranted for individuals who acquired HIV via mother-to-child transmission.

First case of Dolutegravir and Darunavir/r multi drug-resistant HIV-1 in Cameroon following exposure to Raltegravir: lessons and implications in the era of transition to Dolutegravir-based regimens.

BACKGROUND: Sub-Saharan African countries are transitioning to dolutegravir-based regimens, even for patients with extensive previous drug exposure, including first-generation integrase strand-transfer inhibitors (INSTI) such as raltegravir. Such exposure might have implications on cross-resistance to dolutegravir-based antiretroviral therapies (ART). CASE PRESENTATION: We report a 65 years old Cameroonian, previously exposed to raltegravir, and failing on third-line treatment with multi-drug resistance to darunavir/r and dolutegravir. Genotypic resistance testing (GRT) and viral tropism were performed during monitoring time points. The patient initiated ART in August 2007. At the time point of the first (29.04.2010), second (01.12.2017) and third (08.08.2019) GRT, prior ART exposure included 3TC, d4T, NVP and EFV; additionally TDF, DRV/r and RAL; and additionally ABC and DTG respectively. First GRT revealed mutations associated with resistance only to first-generation Non-nucleoside reverse transcriptase inhibitors (NNRTI). Second GRT revealed mutations associated with high-level resistance to all NRTIs, first generation NNRTIs, all ritonavir boosted protease inhibitors (PI/r), and all INSTI, while viral tropism (using geno2pheno) revealed a CCR5-tropic virus with a false positive rate (FPR) of 60.9% suggesting effectiveness of maraviroc (MRV). The third GRT showed high-level resistance to NRTI, NNRTI, all PI and all INSTI, with additional mutations (H221HY for NNRTI and S147G for INSTI), and a CCR5-tropic virus with a slightly reduced FPR (57.0%). Without any locally available active therapeutic option, the patient has been on a maintenance therapy with "DRV/r (600mg x 2/day)+TDF+3TC" and patient/family-centered adherence has been reinforced. Since the first viral load (VL) measurement in 2010, the patient has had 12 VL tests with the VL ranging from 4.97 Log to 6.44 Log copies/mL and the CD4 count never exceeded 200 cells/µL. CONCLUSIONS: As African countries transition to dolutegravir-based regimens, prior raltegravir-exposure may prompt selection (and potential transmission) of dolutegravir-resistance, supporting case surveillance.

Thrombocytopenia according to antiretroviral drug combinations, viremia and CD4 lymphocytes among HIV-infected patients in Cameroon: a snapshot from the City of Yaoundé.

OBJECTIVE: Thrombocytopenia is an abnormal decrease in blood platelets, which can affect the prognosis of people living with HIV (PLHIV). In order to assess the burden of this haematological disorder, we evaluated the frequency of thrombocytopenia according to antiretroviral drug combinations, viremia and the immune status of PLHIV. RESULTS: A cross-sectional and analytical study was conducted from June to November 2016 among 310 PLHIV at the "Chantal BIYA" International Reference Centre, Yaoundé, Cameroon. Overall rate of thrombocytopenia was 19.0% (59/310). The rate of thrombocytopenia was 64.6% (42/65) versus 6.9% (17/245) in ART-naïve versus ART-treated patients respectively, p < 0.0001. Following viral load, rate of thrombocytopenia was 15.8% (20/130) in those with undetectable viral load, and 34.1% (27/79) with viral loads > 3 log10 RNA/ml (p = 0.03). As concerns CD4-count, rate of thrombocytopenia was 16.2% (42/259) in those with ≥ 200 CD4/mm3 versus 33.3% (17/51) with < 200 CD4/mm3 (p = 0.0003). After adjusting for sex, ART, viral load and CD4, Viral load and ART exposure were significantly associated with decreased risk of thrombocytopenia (p < 0.05). Thrombocytopenia occurs especially among ART-naïve, high viremia and severe immune-compromised patients. Interestingly, ART coverage appears as an independent factor in preventing the occurrence of thrombocytopenia.

Phylogenetics of HIV-1 subtype G env: Greater complexity and older origins than previously reported.

HIV-1 subtype G has played an early and central role in the emergent complexity of the HIV-1 group M (HIV-1M) epidemic in central/west Africa. Here, we analysed new subtype G env sequences sampled from 8 individuals in Yaoundé, Cameroon during 2007-2010, together with all publically available subtype G-attributed full-length env sequences with known sampling dates and locations. We inferred that the most recent common ancestor (MRCA) of the analysed subtype G env sequences most likely occurred in ∼1953 (95% Highest Posterior Density interval [HPD] 1939-1963): about 15 years earlier than previous estimates. We found that the subtype G env phylogeny has a complex structure including seven distinct lineages, each likely dating back to the late 1960s or early 1970s. Sequences from Angola, Gabon and the Democratic Republic of Congo failed to group consistently in these lineages, possibly because they are related to more ancient sequences that are poorly sampled. The circulating recombinant form (CRF), CRF06_cpx env sequences but not CRF25_cpx env sequences are phylogenetically nested within the subtype G clade. This confirms that the CRF06_cpx env plausibly was derived through recombination from a subtype G parent, and suggests that the CRF25_cpx env was likely derived from an HIV-1M lineage related to the MRCA of subtype G that has remained undiscovered and may be extinct. Overall, this fills important gaps in our knowledge of the early events in the spread of HIV-1M.

Drug resistance among drug-naive and first-line antiretroviral treatment-failing children in Cameroon.

BACKGROUND: Scale-up to antiretroviral therapy (ART) requires surveillance for HIV drug resistance. With the goal of attaining 100% pediatric ART coverage in Cameroon, strategies to limit the spread of HIV resistance among children are very important. METHODS: From June 2009 through February 2011, 92 HIV-1-infected children (41 ART-naive, 51 failing first-line ART) living in Yaoundé, Cameroon, were enrolled; HIV-1 Prot-RT genotypic resistance testing (GRT) was performed using an inhouse assay. Among 40 children failing first-line ART, treatment response was evaluated at weeks 24 and 48 after treatment was changed, based on GRT results. RESULTS: The mean age was 72 months both for children who were drug-naive and those failing ART (range: 3-144 and 12-144, respectively), with a mean viremia of 5.59 log and 4.71 log RNA copies/mL, a median CD4 of 17% (588 cells/µL) and 23% (719 cells/µL), respectively. Median time-to-treatment failure was 610 days. A prevalence of 4.9% and 90% drug resistance was observed, respectively, among children who were drug-naive and those failing first-line ART, with circulating recombinant form CRF02_AG as the most prevalent clade (58.6% and 62%, respectively). After a change to GRT-based treatment, more than 90% of children had viremia <3 log RNA copies/mL at week 24 and confirmed at week 48, with 70% achieving undetectable viremia, although without correlation to immune response; 97.5% had switched to lopinavir/ritonavir-containing regimens. CONCLUSION: HIV-1 drug resistance was low among ART-naive children and very high among those failing first-line ART. Treatment change based on GRT was successful for most children, with lopinavir/ritonavir regimens being very promising for second-line use.