Drug resistance prevalence and HIV-1 variant characterization in the naive and pretreated HIV-1-infected paediatric population in Madrid, Spain

Global, regional, and national prevalence of HIV-1 drug resistance in treatment-naive and treatment-experienced children and adolescents: a systematic review and meta-analysis

Background

Despite significant reductions in mother-to-child HIV-1 transmission risks due to the advancements and scale-up of antiretroviral therapy (ART), the global burden of HIV-1 drug resistance (HIVDR) in treatment-naive and treatment-experienced children and adolescents remains poorly understood. In this study, we conducted a systematic review and meta-analysis to estimate the prevalence of HIVDR in these populations globally, regionally, and at the country level.

Methods

We systematically searched PubMed, Embase, and Web of Science for studies reporting HIVDR in treatment-naive and treatment-experienced children and adolescents from inception to June 28, 2024. Eligible studies reported at least ten successfully genotyped cases. We excluded studies where drug resistance was not reported separately for children and adults or for treatment-naive and treatment-experienced populations. The methodological quality of eligible studies was assessed, and random-effect models were used for meta-analysis to determine the pooled overall and regimen-specific prevalence of one or more HIVDR mutations in these populations globally, regionally, or at the country level. This study is registered with PROSPERO under the number CRD42023424483.

Findings

Of 2282 records identified, 136 studies (28,539 HIV-1-infected children from 52 countries) were included for analysis. The overall prevalence of HIVDR is 26.31% (95% CI, 20.76-32.25) among treatment-naive children and 74.16% (95% CI, 67.74-80.13) among treatment-experienced children (p < 0.0001). HIVDR varied widely across subregion with the highest prevalence in Southern Africa (37.80% [95% CI, 26.24-50.08]) and lowest in South America (11.79% [95% CI, 4.91-20.84]) for treatment-naive children while highest in Asia (80.85% [95% CI, 63.76-93.55]) and lowest in Europe (54.39% [95% CI, 28.61-79.03]) for treatment-experienced children. The proportion of viral failure (VF) presented positive correlation with DR prevalence for treatment-experienced children, which increased from 61.23% (95% CI, 47.98-73.72) in proportion of VF <50%-81.17% (95% CI, 71.57-89.28) in proportion of 100%. Meta-regression analysis for both groups showed that only age (naive: p = 0.0005; treated: p < 0.0001) was the sources of heterogeneity. Non-nucleoside reverse transcriptase inhibitor (NNRTI) resistances were the most seen mutations among the treatment-naive group, with the HIVDR prevalence more than 10% in Southern Africa, Western and Central Africa, Eastern Africa, Asia, and North America. Both nucleoside reverse transcriptase inhibitor (NRTI) and NNRTI resistances were commonly seen among the treatment-experienced group, varying from 36.33% (95% CI, 11.96-64.93) in North America to 77.54% (95% CI, 62.70-89.58) in South America for NRTI and from 39.98% (95% CI, 13.47-69.97) in Europe to 68.86 (95% CI, 43.91-89.17) in Asia for NNRTI, respectively.

Interpretation

This study underscores the significant burden of HIVDR among children and adolescents worldwide, particularly pronounced in sub-Saharan Africa and low-income countries. It emphasizes the critical importance of surveillance in all HIV-1-infected children and advocates for the adoption of dolutegravir (DTG) or other optimal formulations as first-line ART in settings where NNRTI resistance exceeds the WHO's 10% threshold. DTG's high resistance barrier, potent antiviral efficacy, and favorable safety profile makes it a superior choice for managing drug-resistant HIV-1, surpassing traditional antiretroviral therapies.

Funding

This work was supported by the Science and Technology Innovation Committee of Shenzhen Municipality (No. JCYJ20220531102202005) and the Natural Science Foundation of Guangdong Province (No. 2024A1515012118).

Concordance of genotypic resistance interpretation algorithms in HIV-1 infected patients: An exploratory analysis in Greece

PURPOSE

Genotypic resistance-related mutations in HIV-1 disease are often difficult to interpret. Different algorithms have been developed to provide meaningful application into clinical context. We aimed to compare, for the first time in Greece, the results of genotypic resistance derived from three interpretation algorithms.

METHODS

The sequences of 120 HIV 1-infected patients were tested for genotypic resistance to 19 antiretroviral (ARV) drugs (n = 2280 sequences). The interpretation results of Rega, ANRS and ViroSeq algorithms were compared.

RESULTS

Complete concordance was found for 2/19 ARV drugs, namely lamivudine and emptricitabine. Concordance was high for nucleoside reverse transcriptase inhibitors (NRTIs) and low for protease inhibitors (PIs). In inter-algorithm pairs, agreement was high between Rega and ViroSeq (kappa = 0.701), especially by ARV class, namely NRTIs (k = 0.869) and NNRTIs (k = 0.562). The only exception was noted for rilpivirine, where agreement was higher between ANRS and Rega (k = 0.410) compared to other inter-algorithm pairs (k = 0.018-0.055). By contrast, for PIs all comparisons yielded concordance equivalent to chance (k = 0.000).

CONCLUSIONS

Our exploratory analysis provided evidence of significant inter-algorithm discordances, especially for PIs and NNRTIs highlighting the importance of matching the results of different algorithms to achieve optimized risk stratification. Ongoing research could assist clinical physicians in interpreting complex genotypic resistance patterns.

Impact of Clinical Parameters in the Intrahost Evolution of HIV-1 Subtype B in Pediatric Patients: A Machine Learning Approach

Determining the factors modulating the genetic diversity of HIV-1 populations is essential to understand viral evolution. This study analyzes the relative importance of clinical factors in the intrahost HIV-1 subtype B (HIV-1B) evolution and in the fixation of drug resistance mutations (DRM) during longitudinal pediatric HIV-1 infection. We recovered 162 partial HIV-1B pol sequences (from 3 to 24 per patient) from 24 perinatally infected patients from the Madrid Cohort of HIV-1 infected children and adolescents in a time interval ranging from 2.2 to 20.3 years. We applied machine learning classification methods to analyze the relative importance of 28 clinical/epidemiological/virological factors in the HIV-1B evolution to predict HIV-1B genetic diversity (d), nonsynonymous and synonymous mutations (dN, dS) and DRM presence. Most of the 24 HIV-1B infected pediatric patients were Spanish (91.7%), diagnosed before 2000 (83.3%), and all were antiretroviral therapy experienced. They had from 0.3 to 18.8 years of HIV-1 exposure at sampling time. Most sequences presented DRM. The best-predictor variables for HIV-1B evolutionary parameters were the age of HIV-1 diagnosis for d, the age at first antiretroviral treatment for dN and the year of HIV-1 diagnosis for ds. The year of infection (birth year) and year of sampling seemed to be relevant for fixation of both DRM at large and, considering drug families, to protease inhibitors (PI). This study identifies, for the first time using machine learning, the factors affecting more HIV-1B pol evolution and those affecting DRM fixation in HIV-1B infected pediatric patients.

Impact of lopinavir-ritonavir exposure in HIV-1 infected children and adolescents in Madrid, Spain during 2000-2014

Background

The most-used protease-inhibitor in children is Lopinavir-ritonavir (LPV/r), which provides durable suppression of viral load and increases CD4+T-counts. This study describes the virological outcome of the HIV-1-infected paediatric population exposed to LPV/r during 15 years in Spain.

Methodology

Patients from the Madrid Cohort of HIV-1-infected-children and adolescents exposed to LPV/r as different line therapy during 2000–2014 were selected. The baseline epidemiological-clinical features, viral suppression, changes in CD4+T-CD8+T cell counts and drug susceptibility were recorded before and during LPV/r exposure. Drug resistance mutations (DRM) were identified in viruses from samples collected until 2011. We predicted drug susceptibility to 19 antiretrovirals among those carrying DRM using the Stanford′s HIVdb Algorithm.

Results

A total of 199 (37.3%) of the 534 patients from the cohort were exposed to LPV/r during 2000–2014 in first (group 1), second (group 2) or more line-therapies (group 3). Patients were mainly Spaniards (81.9%), perinatally infected (96.5%) with subtype-B (65.3%) and HIV-diagnosed before year 2000 (67.8%). The mean age at first LPV/r exposure was 9.7 years. After protease-inhibitor exposure, viral suppression was higher in groups 1 and 2 than in group 3. Viral suppression occurred in 87.5%, 68.6% and 64.8% patients from groups 1, 2 and 3, respectively. Among the 64 patients with available resistance data during LPV/r treatment, 27(42.3%) carried DRM to protease-inhibitor, 28 (58.3%) to reverse-transcriptase-inhibitors and 21 (43.7%) to non-reverse-transcriptase-inhibitors. Darunavir/ritonavir, atazanavir-ritonavir and tipranavir/ritonavir presented the highest susceptibility and nelfinavir the lowest.

Conclusions

A better lymphocyte recovering occurred when protease-inhibitor was taken as part of a first-line regimen and a higher number of patients reached viral suppression. The least compromised antiretrovirals for rescue antiretroviral regimens, according to DRM in the LPV/r-exposed-paediatric cohort, were mainly the new protease inhibitors.

Clinical Determinants of HIV-1B Between-Host Evolution and their Association with Drug Resistance in Pediatric Patients

Understanding the factors that modulate the evolution of virus populations is essential to design efficient control strategies. Mathematical models predict that factors affecting viral within-host evolution may also determine that at the between-host level. Although HIV-1 within-host evolution has been associated with clinical factors used to monitor AIDS progression, such as patient age, CD4 cells count, viral load, and antiretroviral experience, little is known about the role of these clinical factors in determining between-host HIV-1 evolution. Moreover, whether the relative importance of such factors in HIV-1 evolution vary in adult and children patients, in which the course of infection is different, has seldom been analysed. To address these questions, HIV-1 subtype B (HIV-1B) pol sequences of 163 infected children and 450 adults of Madrid, Spain, were used to estimate genetic diversity, rates of synonymous and non-synonymous mutations, selection pressures and frequency of drug-resistance mutations (DRMs). The role and relative importance of patient age, %CD4, CD4/mm3, viral load, and antiretroviral experience in HIV-1B evolution was analysed. In the pediatric HIV-1B population, three clinical factors were primary predictors of virus evolution: Higher HIV-1B genetic diversity was observed with increasing children age, decreasing CD4/mm3 and upon antiretroviral experience. This was mostly due to higher rates of non-synonymous mutations, which were associated with higher frequency of DRMs. Using this data, we have also constructed a simple multivariate model explaining between 55% and 66% of the variance in HIV-1B evolutionary parameters in pediatric populations. On the other hand, the analysed clinical factors had little effect in adult-infecting HIV-1B evolution. These findings highlight the different evolutionary dynamics of HIV-1B in children and adults, and contribute to understand the factors shaping HIV-1B evolution and the appearance of drug-resistance mutation in pediatric patients.

Antiretroviral treatment failure, drug resistance, and subtype diversity in the only pediatric HIV clinic in Rhode Island

BACKGROUND

Drug resistance development in the human immunodeficiency virus (HIV)-infected pediatric population in the United States can impact long-term antiretroviral therapy (ART) efficacy. Limited formularies and adherence constraints in children jeopardize lifelong-needed ART.

METHODS

We examined treatment failure, drug resistance, and their correlates in ART-naive and ART-experienced children attending the pediatric HIV clinic in Rhode Island between 1991 and 2012. Pol sequences were obtained for phylogenetic, subtype, and resistance analyses. Associations between selected covariates and virologic failure and resistance were evaluated using generalized additive models and Fisher exact tests.

RESULTS

Data were available for all 56 clinic-attending children. At diagnosis, 33% were aged <1 year, 31% aged 1-4 years, and 37% aged ≥ 5 years; 54% were male, 73% black or Hispanic, 55% US-born, 20% refugees, and 64% perinatally infected. Of 44 ART-experienced children, 57% had virologic failure, most never virologically suppressed. Failure was associated with missed appointments (P = .05) and missed doses (P < .01). Of 40 children with available genotypes, 35% were infected with non-B subtypes; 6% of ART-naive children had resistance; and 73% of ART-experienced children had ≥ 1 major mutation: (16% conferring triple-class, 47% dual-class, and 37% single-class resistance). An epidemiologically confirmed resistance transmission from a perinatally infected teenage male to a newly infected teenage female was demonstrated.

CONCLUSIONS

We report high HIV type 1 diversity, extensive drug resistance among ART-experienced children, and horizontal transmission of resistance in the Rh ode Island pediatric HIV clinic. As HIV-infected children mature into adulthood, close monitoring of ART, adherence, and diagnosis disclosure are essential to optimize patient care.

Relationship between viral load and behavioral measures of adherence to antiretroviral therapy in children living with human immunodeficiency virus in Latin America

Few studies have examined antiretroviral therapy adherence in Latin American children. Standardized behavioral measures were applied to a large cohort of human immunodeficiency virus-infected children in Brazil, Mexico, and Peru to assess adherence to prescribed antiretroviral therapy doses during the three days prior to study visits, assess timing of last missed dose, and evaluate the ability of the adherence measures to predict viral suppression. Time trends in adherence were modeled using a generalized estimating equations approach to account for possible correlations in outcomes measured repeatedly in the same participants. Associations of adherence with human immunodeficiency virus viral load were examined using linear regression. Mean enrollment age of the 380 participants was 5 years; 57.6% had undetectable’ viral load (<400 copies/mL). At enrollment, 90.8% of participants were perfectly (100%) adherent, compared to 87.6% at the 6-month and 92.0% at the 12-month visit; the proportion with perfect adherence did not differ over time (p = 0.1). Perfect adherence was associated with a higher probability of undetectable viral load at the 12-month visit (odds ratio = 4.1, 95% confidence interval: 1.8–9.1; p < 0.001), but not at enrollment or the 6-month visit (p > 0.3). Last time missed any antiretroviral therapy dose was reported as “never” for 52.0% at enrollment, increasing to 60.7% and 65.9% at the 6- and 12-month visits, respectively (p < 0.001 for test of trend). The proportion with undetectable viral load was higher among those who never missed a dose at enrollment and the 12-month visit (p ≤ 0.005), but not at the 6-month visit (p = 0.2). While antiretroviral therapy adherence measures utilized in this study showed some association with viral load for these Latin American children, they may not be adequate for reliably identifying non-adherence and consequently children at risk for viral resistance. Other strategies are needed to improve the evaluation of adherence in this population.

Clinical and virologic follow-up in perinatally HIV-1-infected children and adolescents in Madrid with triple-class antiretroviral drug-resistant viruses

Drug resistance mutations compromise the success of antiretroviral treatment in human immunodeficiency virus type 1 (HIV-1)-infected children. We report the virologic and clinical follow-up of the Madrid cohort of perinatally HIV-infected children and adolescents after the selection of triple-class drug-resistant mutations (TC-DRM). We identified patients from the cohort carrying HIV-1 variants with TC-DRM to nucleoside reverse transcriptase inhibitors, nonnucleoside reverse transcriptase inhibitors and protease inhibitors according to IAS-USA-2013. We recovered pol sequences or resistance profiles from 2000 to 2011 and clinical-immunologic-virologic data from the moment of TC-DRM detection until December 2013. Viruses harbouring TC-DRM were observed in 48 (9%) of the 534 children and adolescents from 2000 to 2011, rising to 24.4% among those 197 with resistance data. Among them, 95.8% were diagnosed before 2003, 91.7% were Spaniards, 89.6% carried HIV-1-subtype B and 75% received mono/dual therapy as first regimen. The most common TC-DRM present in ≥50% of them were D67NME, T215FVY, M41L and K103N (retrotranscriptase) and L90M (protease). The susceptibility to darunavir, tipranavir, etravirine and rilpivirine was 67.7%, 43.7%, 33.3% and 33.3%, respectively, and all reported high resistance to didanosine, abacavir and nelfinavir. Despite the presence of HIV-1 resistance mutations to the three main antiretroviral families in our paediatric cohort, some drugs maintained their susceptibility, mainly the new protease inhibitors (tipranavir and darunavir) and nonnucleoside reverse transcriptase inhibitors (etravirine and rilpivirine). These data will help to improve the clinical management of HIV-infected children with triple resistance in Spain.

Antiretroviral treatment in HIV-1 infected pediatric patients: focus on efavirenz

Efavirenz is a non-nucleoside reverse transcriptase inhibitor (NNRTI), used for the treatment of human immunodeficiency virus (HIV)-1 infection. Approved by the US Food and Drug Administration in 1998, its indication was recently extended to include children as young as 3 months of age. The World Health Organization and many national guidelines consider efavirenz to be the preferred NNRTI for first-line treatment of children over the age of 3 years. Clinical outcomes of patients on three-drug antiretroviral regimens which include efavirenz are as good as or better than those for patients on all other currently approved HIV medications. Efavirenz is dosed once daily and has pediatric-friendly formulations. It is usually well tolerated, with central nervous system side effects being of greatest concern. Efavirenz increases the risk of neural tube defects in nonhuman primates and therefore its use during the first trimester of pregnancy is limited in some settings. With minimal interactions with antituberculous drugs, efavirenz is preferred for use among patients with HIV/tuberculosis coinfection. Efavirenz can be rendered inactive by a single point mutation in the reverse transcriptase enzyme. Newer NNRTI drugs such as etravirine, not yet approved for use in children under the age of 6 years, may maintain their activity following development of efavirenz resistance. This review highlights key points from the existing literature regarding the use of efavirenz in children and suggests directions for future investigation.

HIV-1 drug resistance prevalence, drug susceptibility and variant characterization in the Jacobi Medical Center paediatric cohort, Bronx, NY, USA

OBJECTIVES

With the advent of combined antiretroviral therapy (cART), perinatally HIV-infected children are surviving into adolescence and beyond. However, drug resistance mutations (DRMs) compromise viral control, affecting the long-term effectiveness of ART. The aims of this study were to detect and identify DRMs in a HIV-1 infected paediatric cohort.

METHODS

Paired plasma and dried blood spots (DBSs) specimens were obtained from HIV-1 perinatally infected patients attending the Jacobi Medical Center, New York, USA. Clinical, virological and immunological data for these patients were analysed. HIV-1 pol sequences were generated from samples to identify DRMs according to the International AIDS Society (IAS) 2011 list.

RESULTS

Forty-seven perinatally infected patients were selected, with a median age of 17.7 years, of whom 97.4% were carrying subtype B. They had a mean viral load of 3143 HIV-1 RNA copies/mL and a mean CD4 count of 486 cells/μL at the time of sampling. Nineteen patients (40.4%) had achieved undetectable viraemia (< 50 copies/mL) and 40.5% had a CD4 count of > 500 cells/μL. Most of the patients (97.9%) had received cART, including protease inhibitor (PI)-based regimens in 59.6% of cases. The DRM prevalence was 54.1, 27.6 and 27.0% for nucleoside reverse transcriptase inhibitors (NRTIs), PIs and nonnucleoside reverse transcriptase inhibitors (NNRTIs), respectively. Almost two-thirds (64.9%) of the patients harboured DRMs to at least one drug class and 5.4% were triple resistant. The mean nucleotide similarity between plasma and DBS sequences was 97.9%. Identical DRM profiles were present in 60% of plasma-DBS paired sequences. A total of 30 DRMs were detected in plasma and 26 in DBSs, with 23 present in both.

CONCLUSIONS

Although more perinatally HIV-1-infected children are reaching adulthood as a result of advances in cART, our study cohort presented a high prevalence of resistant viruses, especially viruses resistant to NRTIs. DBS specimens can be used for DRM detection.

Description of HIV-1 group M molecular epidemiology and drug resistance prevalence in Equatorial Guinea from migrants in Spain

Background

The HIV epidemic is increasing in Equatorial Guinea (GQ), West Central Africa, but few studies have reported its HIV molecular epidemiology. We aimed to describe the HIV-1 group M (HIV-1M) variants and drug-resistance mutations in GQ using sequences sampled in this country and in Spain, a frequent destination of Equatoguinean migrants.

Methods

We collected 195 HIV-1M pol sequences from Equatoguinean subjects attending Spanish clinics during 1997-2011, and 83 additional sequences sampled in GQ in 1997 and 2008 from GenBank. All (n = 278) were re-classified using phylogeny and tested for drug-resistance mutations. To evaluate the origin of CRF02_AG in GQ, we analyzed 2,562 CRF02_AG sequences and applied Bayesian MCMC inference (BEAST program).

Results

Most Equatoguinean patients recruited in Spain were women (61.1%) or heterosexuals (87.7%). In the 278 sequences, the variants found were CRF02_AG (47.8%), A (13.7%), B (7.2%), C (5.8%), G (5.4%) and others (20.1%). We found 6 CRF02_AG clusters emerged from 1983.9 to 2002.5 with origin in GQ (5.5 sequences/cluster). Transmitted drug-resistance (TDR) rate among naïve patients attended in Spain (n = 144) was 4.7%: 3.4% for PI (all with M46IL), 1.8% for NRTI (all with M184V) and 0.9% for NNRTI (Y188L). Among pre-treated patients, 9/31 (29%) presented any resistance, mainly affecting NNRTI (27.8%).

Conclusions

We report a low (<5%) TDR rate among naïve, with PI as the most affected class. Pre-treated patients also showed a low drug-resistance prevalence (29%) maybe related to the insufficient treatment coverage in GQ. CRF02_AG was the prevalent HIV-1M variant and entered GQ through independent introductions at least since the early 1980s.

A new tool for the paediatric HIV research: general data from the Cohort of the Spanish Paediatric HIV Network (CoRISpe)

There are approximately from 1,100 to 1,200 HIV-infected children in a follow-up in Spain. In 2008 an open, multicentral, retrospective and prospective Cohort of the Spanish Paediatric HIV Network (CoRISpe) was founded. The CoRISpe is divided into the node 1 and node 2 representing geographically almost the whole territory of Spain. Since 2008 seventy-five hospitals have been participating in the CoRISpe. All the retrospective data of the HIV-infected children have been kept in the CoRISpe since 1995 and prospective data since 2008. In this article we are going to present the notion of CoRISpe, its role, the structure, how the CoRISpe works and the process how a child is transferred from Paediatric to Adults Units. The main objective of the CoRISpe is to contribute to furthering scientific knowledge on paediatric HIV infection by providing demographic, sociopsychological, clinical and laboratory data from HIV-infected paediatric patients. Its aim is to enable high-quality research studies on HIV-infected children.

High drug resistance prevalence among vertically HIV-infected patients transferred from pediatric care to adult units in Spain

BACKGROUND

Antiretroviral treatment (ART) has contributed to increased life expectancy of HIV-1 infected children. In developed countries, an increasing number of children reaching adulthood are transferred to adult units. The objectives were to describe the demographic and clinical features, ART history, antiviral drug resistance and drug susceptibility in HIV-1 perinatally infected adolescents transferred to adult care units in Spain from the Madrid Cohort of HIV-1 infected children.

METHODS

Clinical, virological and immunological features of HIV-1 vertically infected patients in the Madrid Cohort of HIV-infected children were analyzed at the time of transfer. Pol sequences from each patient were recovered before transfer. Resistance mutations according to the InternationaI AIDS Society 2011 list were identified and interpreted using the Stanford algorithm. Results were compared to the non-transferred HIV-1 infected pediatric cohort from Madrid.

RESULTS

One hundred twelve infected patients were transferred to adult units between 1997 and 2011. They were mainly perinatally infected (93.7%), with a mean nadir CD4+-T-cells count of 10% and presented moderate or severe clinical symptoms (75%). By the time of transfer, the mean age was 18.9 years, the mean CD4+T-cells count was 627.5 cells/ml, 64.2% presented more than 350 CD4+T-cells/ml and 47.3% had ≤ 200 RNA-copies/ml. Most (97.3%) were ART experienced receiving Highly Active ART (HAART) (84.8%). Resistance prevalence among pretreated was 50.9%, 76.9% and 36.5% for Protease Inhibitors (PI), Nucleoside Reverse Transcriptase Inhibitors (NRTI) and Non-NRTI (NNRTI), respectively. Resistance mutations were significantly higher among transferred patients compared to non-transferred for the PI+NRTI combination (19% vs. 8.4%). Triple resistance was similar to non-transferred pediatric patients (17.3% vs. 17.6%).

CONCLUSION

Despite a good immunological and virological control before transfer, we found high levels of resistance to PI, NRTI and triple drug resistance in HIV-1 infected adolescents transferred to adult units.

High viremia and low level of transmitted drug resistance in anti-retroviral therapy-naïve perinatally-infected children and adolescents with HIV-1 subtype C infection

Background

High plasma viremia in HIV-1 infection is associated with rapid CD4 cell decline and faster disease progression. Children with HIV infection have high viral loads, particularly in early childhood. In this study we sought to understand the relationship between duration of HIV-1 infection and viral dynamics among perinatally-infected children and adolescents in India along with transmitted drug resistance in this population.

Methods

During 2007–2011, cross-sectional samples were collected from ART-naïve children (n = 105) with perinatally-acquired HIV infection, aged 2–16 years from Bangalore, India. CD4 counts, viral load and in-house genotyping were performed and transmitted drug resistance mutations were identified using the World Health Organization recommendations for Surveillance of Drug Resistance Mutations (SDRM_2009) list.

Results

Among 105 children studied, 73.3% (77/105) were asymptomatic, but had a median viral load of 5.24 log copies/mL (IQR 4.62-5.66). In the adolescent age group, 54% (21/39) had high levels of viremia (median 5.14 log copies/mL) but were asymptomatic. HIV-1 subtyping identified 98% strains (103/105) as subtype C; one A1 and one unique recombinant form (URF). Transmitted NRTI resistance was 1.9% (2/105); NNRTI resistance was 4.8% (5/105) and overall prevalence of transmitted drug resistance was 5.7% (6/105).

Conclusions

The high burden of plasma viremia found among untreated asymptomatic adolescents needs to be addressed both from an individual angle to halt disease progression, and from a public health perspective to arrest horizontal transmission. The low level of transmitted drug resistance among perinatally-infected children is reassuring; however with improving ART access globally, regular genotyping surveillance is indicated.

Sexual risk behavior among youth with perinatal HIV infection in the United States: predictors and implications for intervention development

BACKGROUND

Factors associated with initiation of sexual activity among perinatally human immunodeficiency virus (HIV)-infected (PHIV(+)) youth, and the attendant potential for sexual transmission of antiretroviral (ARV) drug-resistant HIV, remain poorly understood.

METHODS

We conducted cross-sectional and longitudinal analyses of PHIV(+) youth aged 10-18 years (mean, 13.5 years) enrolled in the US-based Pediatric HIV/AIDS Cohort Study between 2007 and 2009. Audio computer-assisted self-interviews (ACASI) were used to collect sexual behavior information.

RESULTS

Twenty-eight percent (95% confidence interval [CI], 23%-33%) (92/330) of PHIV(+) youth reported sexual intercourse (SI) (median initiation age, 14 years). Sixty-two percent (57/92) of sexually active youth reported unprotected SI. Among youth who did not report history of SI at baseline, ARV nonadherence was associated with sexual initiation during follow-up (adjusted hazard ratio, 2.87; 95% CI, 1.32-6.25). Youth living with a relative other than their biological mother had higher odds of engaging in unprotected SI than those living with a nonrelative. Thirty-three percent of youth disclosed their HIV status to their first sexual partner. Thirty-nine of 92 (42%) sexually active youth had HIV RNA ≥5000 copies/mL after sexual initiation. Viral drug resistance testing, available for 37 of these 39 youth, identified resistance to nucleoside reverse transcriptase inhibitors in 62%, nonnucleoside reverse transcriptase inhibitors in 57%, protease inhibitors in 38%, and all 3 ARV classes in 22%.

CONCLUSIONS

As PHIV(+) youth become sexually active, many engage in behaviors that place their partners at risk for HIV infection, including infection with drug-resistant virus. Effective interventions to facilitate youth adherence, safe sex practices, and disclosure are urgently needed.

Trends in drug resistance prevalence in HIV-1-infected children in Madrid: 1993 to 2010 analysis

BACKGROUND

Drug resistance mutations compromise antiretroviral treatment (ART) effectiveness in HIV-1-infected children. Trends in drug resistance prevalence have not been previously evaluated in HIV-infected children in Spain.

METHODS

HIV-1 variants, drug resistance prevalence dynamics and drug susceptibility were analyzed from 1993 to 2010 in HIV-infected children with available pol sequence, sample or drug resistance profile. HIV-1 variants were characterized by phylogenetic analysis. Resistance mutations in pretreated and naive patients were identified according to International AIDS Society-2010 and the World Health Organization list, respectively.

RESULTS

In 232 patients, genotypic resistance profiles (n = 11) or pol sequences (n = 128) were recovered or newly generated from infected samples (n = 93). Patients were mainly in care at pediatric units (63%), were mostly Europeans (84%), with moderate AIDS symptoms (65%), on ART (91%) and infected by HIV-1 subtype B (89%). Transmitted major drug resistance mutations were selected in 6 (13.6%) of the 44 ART-naive children: 4.8%, 9.3% and 11.6%, for protease inhibitors, nucleoside reverse transcriptase inhibitors and nonnucleoside reverse transcriptase inhibitors, respectively. Overall resistance prevalence was higher (71.8%) among ART-exposed children: 39.9%, 66.5% and 35.3% for protease inhibitors, nucleoside reverse transcriptase inhibitors and nonnucleoside reverse transcriptase inhibitors, respectively. Resistance prevalence among ART-exposed children was higher in 2009 to 2010 relative to 1993 to 1999 for nonnucleoside reverse transcriptase inhibitors (42% versus 6%; P = 0.006), protease inhibitors (39% versus 13%; P = 0.004) and nucleoside reverse transcriptase inhibitors (63% versus 44%; P = NS). Susceptibility to each drug in resistant viruses was predicted. The rate of non-B infections increased in the last years, mainly caused by recombinant viruses.

CONCLUSIONS

The increasing resistance prevalence among the HIV-infected pediatric population in Spain highlights the importance of specific drug resistance and drug susceptibility surveillance in long-term pretreated children to optimize treatment regimens.

An outbreak of HIV-1 BC recombinants in Southern Italy

BACKGROUND

In Western Europe, a previously subtype B HIV-1 restricted area, BC recombinants have been rarely reported.

OBJECTIVE

To describe an outbreak of HIV-1 BC recombinants in southern Italy.

STUDY DESIGN

We analyzed pol (protease/reverse transcriptase) sequences from 135 newly diagnosed HIV-1-infected patients during the years 2009-2011. For phylogenetic relationships, sequences were aligned to the most recent reference data set from the Los Alamos database using BioEdit (version 7.1.3). The resulting alignment was analyzed with the Phylip package (version 3.67) building a neighbor-joining tree based on the Kimura two-parameter substitution model. The reliability of the tree topology was assessed through bootstrapping using 1000 replicates. The recombination pattern was characterized using SimPlot 3.5.1 and SplitsTree 4.

RESULTS

At phylogenetic analysis, 22 (16.2%) isolates whose sequences were not unequivocally assigned to a pure subtype or known CRF, formed a distinct monophyletic clade (100% of bootstrap value). For these isolates, the recombination analysis identified a BC mosaic pattern with two breakpoints at positions 2778±5 and 3162±8 (HXB2 numbering) which differed from those of known BC CRFs. All patients from whom these sequences were derived were highly educated youth Italians, 91% males and 82% MSM. Sequences of pol integrase, gp120 and gp41 from these same patients were classified as C subtype.

CONCLUSIONS

This outbreak which further reflects the increasing heterogeneity of HIV epidemic in our country is the first report of an Italian outbreak of a BC recombinant, possibly a novel candidate CRF.