HIV viral load response to antiretroviral therapy according to the baseline CD4 cell count and viral load

ViraLite: An Ultracompact HIV Viral Load Self-Testing System with Internal Quality Control

The availability of effective antiretroviral therapy has made HIV manageable, provided patients have consistent access to routine viral load (VL) testing. Nonetheless, access to frequent VL testing remains limited. There is a need for accessible, user-friendly testing systems that allow people living with HIV (PLHIV) to monitor their VL more frequently and empower self-management. Here, we developed ViraLite, a sample-to-answer, compact, accessible, and battery-powered system for HIV viral load monitoring. The system is built upon a probe-based RT-LAMP assay that allows for multiplexed detection and quantification. An internal quality control targeting the RNase P was incorporated to enhance the reliability of the results. A software-reconfigurable real-time sensing system empowered by machine learning and a smartphone-guided protocol was developed in tandem to analyze the multiplexed assay. We analyzed 45 clinically archived samples using ViraLite and benchmarked our results against qRT-PCR, which showed 21 positive and 23 negative samples. Using our process control, ViraLite first identified 17 inconclusive samples that would otherwise be classified as negative. Then, ViraLite classified 14 out of 15 HIV-positive samples (93.3%) and 13 out of 13 HIV-negative samples (100%). The incorporation of RNase P as a process control increased the sensitivity of ViraLite from 66.66% to 93.33%, while maintaining a high specificity (100%). To assess the acceptance of ViraLite among PLHIV, we recruited 480 participants from online and three clinical sites to complete a survey. Over 86% of participants indicated ViraLite had benefits in convenience and privacy, on the other hand 61% of participants indicated concerns with test accuracy. The integration of compact hardware, a reliable assay, and smartphone guidance provides an accurate, easy to use system for PLHIV to self-manage their viral load and update their prescriptions frequently.

Comparative evaluation of plasma and serum HIV-1 viral load measurements among HIV positive individuals, Northwest Ethiopia: Analytical cross-sectional study

INTRODUCTION

Plasma HIV viral load tests have been widely used in clinical practice to monitor treatment success or failure. Inappropriate mixing with anticoagulants and inaccessibility of plasma samples in certain clinical services (such as antenatal care services) might hinder HIV diagnosis and treatment services. Considering that serum has higher stability and availability in prenatal care services, periodic monitoring of serum HIV viral load might be an alternative approach. Thus, this study aimed to evaluate the plasma and serum HIV-1 viral load measurements among HIV-positive individuals in Northwest Ethiopia.

METHODS

An institution-based analytical cross-sectional study was conducted on 74 paired plasma and serum samples from May to August 2020 at the HIV Treatment Center, Northwest Ethiopia. Four milliliters of paired venous blood were collected to harvest plasma and serum. HIV-1 RNA was extracted and quantified using the Roche COBAS AmpliPrep/COBAS TaqMan assay. Data were analyzed using SPSS version 20. Paired sample t-tests and Pearson's correlation were employed to observe the mean differences and associations between sample measurements, respectively. Bland-Altman and linear regression models were computed to demonstrate the level of agreement and proportional bias, respectively. A p-value of ≤  0.05 with a 95% confidence interval was considered statistically significant.

RESULTS

From a total of 74 HIV-positive individuals, 49 (66.2%) were females. The mean ±  SD age was 36.3 (10.1) years. The mean difference ±  SD of plasma and serum HIV-1 viral load was 0.07 ±  0.75 log copies/mL, (p =  0.428). A strong association with a significant linear correlation (r =  0.862) (p < 0.001) and a high level of agreement were observed between the sample measurements using Pearson's correlation and a Bland-Altman plot, respectively.

CONCLUSIONS

The current study highlights an alternative application of serum-based HIV viral load quantification to enhance the rate of HIV diagnosis and treatment monitoring coverage.

Longitudinal Viral Load Clustering for People With HIV Using Functional Principal Component Analysis

Background: Longitudinal measures of viral load (VL) are critical in monitoring the HIV status. While multiple lab indicators exist for monitoring measures of VL, research on clustering historical/longitudinal VL measures is limited. Analyzing longitudinal VL patterns rather than aggregated measures offers deeper insights into HIV status. This study uses functional data clustering to classify longitudinal VL patterns and characterize each cluster by demographics, comorbidities, social behaviors, and CD4 count. Methods: Adult PWH diagnosed from 2005 to 2015 in South Carolina with a 5-year minimum follow-up were included. We compared functional principal component analysis (FPCA), K-means, hierarchical clustering, and Gaussian mixture models for classification and found FPCA yielded the best results. ANOVA was used to compare VL characteristics, demographics, comorbidities, substance uses, and longitudinal CD4 count across clusters. Results: Results obtained from FPCA could best distinguish the characteristics and patterns into four clusters. A total of 5916 PWH were grouped into long-term VS group (Cluster 1, 17.3%), short-term VS group (Cluster 2, 29.8%), suboptimal VS group (Cluster 3, 28.3%), and viral failure group (Cluster 4, 24.9%). In the long-term VS group with an average of 11-year follow-up, PWH displayed sustained VS (95.3%) and lower mean CD4 count (95.3%) than other clusters. The short-term VS group had shorter follow-up (6 years), more comorbidities (31.4%), and lower percentage of time with low CD4 count (79.9%). In suboptimal VS group, PWH were mostly under 30 years old (44.8%) and Black (77.2%), with relatively lower mean VL (92.9%) and lower VR history (18.4%). In the viral failure group, PWH had higher mean VL (40.6%) and lower mean CD4 count (34.7%). Discussion: The findings highlight the impact of continuous clustering in understanding the distinct viral profiles of PWH and emphasize the importance of tailored treatment and insights to target interventions for all PWH.

Viral load undetectable state and predictors among children and adolescents living with HIV in South Gondar, Ethiopia, 2023: an 8-year retrospective cohort study

OBJECTIVES

The objective of this study is to examine the zonal-wide load undetectable state and predictors among children and adolescents living with HIV at South Gondar health institutions, 2023.

DESIGN

A retrospective cohort study.

SETTING

South Gondar Health Institutions, Northwest, Ethiopia.

PARTICIPANTS

We recruited 430 children and adolescents living with HIV who had a follow-up at the antiretroviral therapy (ART) clinic at health institutions from 1 June 2016 to 30 April 2023.

OUTCOME MEASURES

The primary outcome measure of this study was the viral load undetectable state estimation. Moreover, the study assessed the median time viral load undetectable state and its predictors by the Cox-proportional hazard model. Data were entered into Epi-data V.4.2 and exported to STATA V.17 statistical software for analysis.

RESULTS

The mean follow-up period was 8.5 (95% CI 8.1 to 8.9)±4.4 SD months, overall yielding 9151 person-month observations. At the end of the follow-up, 369 (85.8%, 95% CI 82.6% to 88.8%) of the children and adolescents achieved the viral load undetected state. Moreover, the overall median survival time to develop viral load undetectable state was found to be 6 months.The viral load undetected state in children and adolescents who have a cluster of differentiation 4 (CD4) count above the threshold level was 2.8 times higher than those in children and adolescents with a CD4 count lower than the threshold level (adjusted HR (AHR) 2.8 (95% CI 1.5, 5.3)). Likewise, the viral load undetected state in children and adolescents who have a good level of ART adherence was 2.0 times higher than those children and adolescents with a fair/poor level of ART adherence (AHR 2.0 (95% CI 1.1, 3.9)). Moreover, children and adolescents who had nutritional status ≥-2 Z score increased a viral load undetected state by 2.3 times as compared with children and adolescents with nutritional status <-2 Z score (AHR 2.3 (95% CI 1.3, 4.0)). Furthermore, children and adolescents who had no treatment failure increased a viral load undetected state by 2.1 times as compared with children and adolescents who had treatment failure (AHR 3.0 (95% CI 1.1, 4.0).

CONCLUSION

The lower proportion of individuals achieving an undetectable viral load compared with the target set by the WHO strategic plan (95-95-95 target by 2025), highlights the need for targeted interventions and improved HIV management strategies. Factors such as CD4 count, ART adherence, nutritional status and treatment failure play a significant role in achieving viral load undetectable state. Healthcare providers better prioritise these factors through comprehensive care and support. The study emphasises the importance of aligning efforts with the WHO strategic plan to meet targets and improve treatment outcomes. Therefore, stakeholders better address the identified predictors to enhance care and support for this vulnerable population.

Determinants of virological failure among HIV clients on second-line antiretroviral treatment at Felege-hiwot and University of Gondar comprehensive specialized hospitals in the Amhara Region, Northwest Ethiopia: A case-control study

BACKGROUND

Second-line HIV treatment failure has become increasing worldwide, mainly in sub-Sahara Africa including Ethiopia. Even though the problem becomes increasing, inadequate information was available about its magnitude and associated factors in the current study area.

OBJECTIVE

To assess the factors of second-line Anti-Retroviral Treatment virological failure among second-line ART users.

METHOD AND MATERIALS

Institutional-based unmatched case-control study design was conducted from September to December 2021 at Felege Hiowt and University of Gondar Comprehensive Specialized Hospitals; Amhara region, Northwest Ethiopia. A total of 216 patients (60 cases and 156 controls) were recruited by a simple random sampling technique with a 1:3 cases-to-controls ratio. Patients who had two viral load results >1000 copies/ml within a 3-month interval after taking ART drugs for at least 6 months were cases and those who had ≤1,000 copies/ mL were controls. The sample size was calculated by using Epi-Info version 7.2.4. Structured questionnaires were used to gather the required information. SPSS version 26 was used to summarize the findings. In bivariate logistic regression model, Variables with two-tailed P-value ≤ 0.25 at 95% confidence interval were transferred into multivariate binary logistic regression model and P value at ≤ 0.05 was set as statistically significant.

RESULTS

Out of 216 patients recruited, 212 have participated with a response rate of 98.2%. From these participants, 117(55.2%) were males and 187(88.2%) were urban dwellers. Among the total respondents, 208(98.1%) had age > 24 years, 200(94.3) were at HIV clinical stage I, 72(34%) had poor ART adherence and 112(52.8) did not disclose their HIV status. Likewise, most of the patients 147(69.37) didn't use condoms. The associated factors were not disclosing HIV status (AOR = 3.4, 95% CI: 1.52-7.79), medium adherence (AOR = 3.7, 95% CI = 1.3-10.7), poor adherence level (AOR = 5.27, 95% CI: 2.2-12.5), not using condoms (AOR = 4.47, 95% CI: 1.63-12.2) and Viral load (>150 copies/ml) when switched to second-line ART (AOR = 3.56, 95% CI: 1.5-8).

CONCLUSION AND RECOMMENDATIONS

Non-disclosure, poor or medium adherence, not using condoms and high Viral load (>150 copes/ml) when switched to second-line ART were the main factors for second-line Anti-Retroviral Treatment virological failure. Disclosure about HIV status, using condoms and improving treatment adherence level are crucial to reduce second-line virological failure.

Low-Level Viremia among Adults Living with HIV on Dolutegravir-Based First-Line Antiretroviral Therapy Is a Predictor of Virological Failure in Botswana

We evaluated subsequent virologic outcomes in individuals experiencing low-level virem ia (LLV) on dolutegravir (DTG)-based first-line antiretroviral therapy (ART) in Botswana. We used a national dataset from 50,742 adults who initiated on DTG-based first-line ART from June 2016-December 2022. Individuals with at least two viral load (VL) measurements post three months on DTG-based first-line ART were evaluated for first and subsequent episodes of LLV (VL:51-999 copies/mL). LLV was sub-categorized as low-LLV (51-200 copies/mL), medium-LLV (201-400 copies/mL) and high-LLV (401-999 copies/mL). The study outcome was virologic failure (VF) (VL ≥ 1000 copies/mL): virologic non-suppression defined as single-VF and confirmed-VF defined as two-consecutive VF measurements after an initial VL < 1000 copies/mL. Cox regression analysis identified predictive factors of subsequent VF. The prevalence of LLV was only statistically different at timepoints >6-12 (2.8%) and >12-24 (3.9%) (p-value < 0.01). LLV was strongly associated with both virologic non-suppression (adjusted hazards ratio [aHR] = 2.6; 95% CI: 2.2-3.3, p-value ≤ 0.001) and confirmed VF (aHR = 2.5; 95% CI: 2.4-2.7, p-value ≤ 0.001) compared to initially virally suppressed PLWH. High-LLV (HR = 3.3; 95% CI: 2.9-3.6) and persistent-LLV (HR = 6.6; 95% CI: 4.9-8.9) were associated with an increased hazard for virologic non-suppression than low-LLV and a single-LLV episode, respectively. In a national cohort of PLWH on DTG-based first-line ART, LLV > 400 copies/mL and persistent-LLV had a stronger association with VF. Frequent VL testing and adherence support are warranted for individuals with VL > 50 copies/mL.

Booster vaccination is required to elicit and maintain COVID-19 vaccine-induced immunity in SIV-infected macaques

ABSTRACTProlonged infection and possible evolution of SARS-CoV-2 in patients living with uncontrolled HIV-1 infection highlight the importance of an effective vaccination regimen, yet the immunogenicity of COVID-19 vaccines and predictive immune biomarkers have not been well investigated. Herein, we report that the magnitude and persistence of antibody and cell-mediated immunity (CMI) elicited by an Ad5-vectored COVID-19 vaccine are impaired in SIV-infected macaques with high viral loads (> 10⁵ genome copies per ml plasma, SIV^hi) but not in macaques with low viral loads (< 10⁵, SIV^low). After a second vaccination, the immune responses are robustly enhanced in all uninfected and SIV^low macaques. These responses also show a moderate increase in 70% SIV^hi macaques but decline sharply soon after. Further analysis reveals that decreased antibody and CMI responses are associated with reduced circulating follicular helper T cell (TFH) counts and aberrant CD4/CD8 ratios, respectively, indicating that dysregulation of CD4⁺ T cells by SIV infection impairs the COVID-19 vaccine-induced immunity. Ad5-vectored COVID-19 vaccine shows no impact on SIV loads or SIV-specific CMI responses. Our study underscores the necessity of frequent booster vaccinations in HIV-infected patients and provides indicative biomarkers for predicting vaccination effectiveness in these patients.

Efficacy of Dolutegravir versus Darunavir in Antiretroviral First-Line Regimens According to Resistance Mutations and Viral Subtype

Background: Dolutegravir (DTG)-based first-line regimens have shown superior efficacy versus darunavir (DRV)-based ones in randomized trials. We compared these two strategies in clinical practice, particularly considering the role of pre-treatment drug resistance mutations (DRMs) and of the HIV-1 subtype. Materials and methods: The multicenter Antiretroviral Resistance Cohort Analysis (ARCA) database was queried to identify HIV-1-positive patients starting a first-line therapy with 2NRTIs plus either DTG or DRV between 2013 and 2019. Only adult (≥18 years) patients with a genotypic resistance test (GRT) prior to therapy and with HIV-1 RNA ≥1000 copies/mL were selected. Through multivariable Cox regressions, we compared DTG- versus DRV-based regimens in the time to virological failure (VF) stratifying for pre-treatment DRMs and the viral subtype. Results: A total of 649 patients was enrolled, with 359 (55.3%) and 290 (44.7) starting DRV and DTG, respectively. In 11 months of median follow-up time, there were 41 VFs (8.4 in 100 patient-years follow-up, PYFU) and 15 VFs (5.3 per 100 PYFU) in the DRV and DTG groups, respectively. Compared with a fully active DTG-based regimen, the risk of VF was higher with DRV (aHR 2.33; p = 0.016), and with DTG-based regimens with pre-treatment DRMs to the backbone (aHR 17.27; p = 0.001), after adjusting for age, gender, baseline CD4 count and HIV-RNA, concurrent AIDS-defining event and months since HIV diagnosis. Compared with patients harboring a B viral subtype and treated with a DTG-based regimen, patients on DRV had an increased risk of VF, both in subtype B (aHR 3.35; p = 0.011), C (aHR 8.10; p = 0.005), CRF02-AG (aHR 5.59; p = 0.006) and G (aHR 13.90; p < 0.001); DTG also demonstrated a reduced efficacy in subtypes C (versus B, aHR 10.24; p = 0.035) and CRF01-AE (versus B; aHR 10.65; p = 0.035). Higher baseline HIV-RNA and a longer time since HIV diagnosis also predicted VF. Conclusions: In line with randomized trials, DTG-based first-line regimens showed an overall superior efficacy compared with DRV-based regimens. GRT may still play a role in identifying patients more at risk of VF and in guiding the choice of an antiretroviral backbone.

Predictors of Viral Load Status Over Time Among HIV Infected Adults Under HAART in Zewditu Memorial Hospital, Ethiopia: A Retrospective Study

Background

HIV attacks the CD4 cells which are responsible for the body's immune response to infectious agents. The main objective of this study was to identify predictors of viral load status over time among HIV patients under HAART in Zewditu Memorial Hospital.

Methods

A retrospective institutional-based cohort study design was conducted on 161 HIV-infected adults under HAART whose follow-ups were from January 2014 up to December 2017. A generalized linear mixed-effects model was conducted to infer predictors of the status of viral load at 95% of CI).

Results

The descriptive statistics revealed that about 55.9% of the adults under treatment had a detected viral load status. Among the potential predictors, visiting time of patients (AOR = 0.731, 95%: (0.634,0.842) and p-value <0.01), age of patients (AOR = 1.0666, 95% CI: (1.0527,1.0917) and p-value <0.01), weight (AOR=. 0.904, 95% CI: (0.862, 0.946) and p-value <0.01), baseline CD4 cell count (AOR = 0.996, 95% CI: (0.994, 0.998) and P-value <0.01), educated patients (AOR = 0.030, 95% CI: (0.002, 0.385) and p-value=0.0053), rural patients (AOR = 6.30,95% CL: (1.78, 2.25) and p-value=0.0043), working status patients (AOR = 0.5905, 95% CI: (0.547,0.638), p-value <0.01), poor adherent patients (AOR = 1.120, 95% CI; (1.035,1.391) and p-value = 0.016) and patients disclosed the disease status (AOR = 0.195, 95% CI: (0.023, 0.818) and p-value=0.0134) significantly affected the detection status of viral loads, keeping all other covariates constant.

Conclusion

The predictor variables; visiting times, the weight of patients, residence area, age of patients, educational level, clinical stages, functional status, baseline CD4 cell count, adherence status, and disclosure status of the disease statistically and significantly affected the status of viral load. Hence, health-related education should be given for patients to disclose their disease status, to be good adherents based on the prescription given to the health staff. Due attentions should be given for rural and uneducated patients. Attention should be forwarded to for non-adherent patients to follow the instruction given by the health staff.

Toxoplasma gondii, HBV, and HCV co-infection and their correlation with CD4 cells among Iranian HIV-positive patients

INTRODUCTION

Human immunodeficiency virus (HIV/AIDS) infected patients have a higher risk of opportunistic infections (OIs) depending on their immunological status, especially CD4 + cell count. Toxoplasma gondii, hepatitis C virus (HCV), and hepatitis B virus (HBV) are important OIs among Human Immunodeficiency Virus (HIV)/Acquired Immune Deficiency Syndrome (AIDS) patients. However, little is known about co-infection of these pathogens among HIV-infected individuals and their correlation with the patient's CD4 + cell count. Hence, this study aimed to investigate the serological and molecular status of T. gondii infection among HIV-infected individuals who had co-infection with HBV and HCV infections.

METHODS

A total of 100 HIV/AIDS patients in two cities in the southwest of Iran was tested for T. gondii Immunoglobulin G (IgG) and Immunoglobulin M (IgM) antibodies as well as DNA detection by polymerase chain reaction (PCR) targeting the RE gene. HBV and HCV were detected by hepatitis B surface antigen (HBsAg) test, hepatitis C antibody (HCV Ab) test, and Real-Time PCR. The number of CD4 + cell counts was determined by Flow cytometry.

RESULTS

Anti-T. gondii IgG was positive in 22% of the patients, but anti-T. gondii IgM and PCR were negative in all samples. HBV and HCV were positive in 8% and 33% of the patients, respectively. Co-infections were as followed: HIV + HCV (16%), HIV + HCV + T. gondii (11%), HIV + T. gondii (5%), HIV + HBV (1%), HIV + HBV + T. gondii (1%), HIV + HBV + HCV (1%), and HIV + HBV + HCV + T. gondii (5%). A significant decline in CD4 + cell counts was found in such co-infection groups (HIV + T. gondii, HIV + HCV + T. gondii, and HIV + HBV + HCV + T. gondii) compared with the HIV mono-infection group.

CONCLUSIONS

Our study showed that co-infections of T. gondii, HCV, and HBV were common among HIV-infected patients and co-infections had a negative correlation with CD4 + cell counts of the patients.

Analysis of virological response to therapy and resistance profile in treatment-experienced and naive HIV-1 infected Romanian patients receiving regimens containing darunavir boosted with ritonavir or cobicistat

77% of Romanians infected with HIV receive antiretroviral therapy, with the challenge of maintaining long-term therapeutic success (the viral load becoming/remaining undetectable). The main purpose of this study was to provide comparative analysis of the long-term virological response to therapeutic regimens containing pharmacokinetically enhanced darunavir (DRV) with ritonavir (RTV) or cobicistat (COBI). The second aim was to evaluate the viral resistance profile to therapy, by number/type/frequency of viral mutations. This retrospective study was conducted on 462 patients infected with subtype F HIV-1, registered at the "Matei Bals" National Institute of Infectious Diseases, between 2018 and 2021: 384 patients received (among other ARV) DRV 600 mg, enhanced with RTV 100 mg (twice daily) and 78 patients received DRV 800 mg boosted with COBI 150 mg (once daily). The virological response was measured by determining the viral load (HIV-1 RNA copies/mL), while the incidence of viral resistance to therapy was assessed by genotyping tests. Comparing the patients with undetectable viremia, from the 1st visit to the 3rd one, the outcomes showed that at the last visit, 84.6% subjects in the DRV/c group achieved virological efficiency over those from DRV/r group (76.8%). The differences observed between this time points are statistically significant p < 0.05. DRV/c administered in combination with other ARV, in subtype F HIV-1 infected patients, proved to be more virologically effective, maintaining a favorable long-time result. When comparing the outcomes of the two groups, a statistically significant difference of p < 0.05 was obtained. 32 patients (27 from DRV/r group and 5 from DRV/c group) were evaluated with persistent HIV-1 ARN plasma load > 1000 copies/mL, during all 3 clinical visits. They formed a research sub-group evaluated in terms of resistance to therapy and were reported as virological failures. 28.12% of the sub-group with persistent HIV-1 RNA > 1000 copies/mL were from the DRV/r group and only 3.12% from the DRV/c group. Drug mutations (DRM) involved in antiretroviral resistance/sensitivity occurred both in the protease gene, and in the reverse transcriptase gene, with the involved ARV classes being protease inhibitors, nucleoside reverse transcriptase inhibitors, non-nucleoside reverse transcriptase inhibitors. 16 different types of mutations were evaluated in the PR gene and 20 mutations were evaluated in RT gene.

Functional compartmentalization of antibodies in the central nervous system during chronic HIV infection

The central nervous system (CNS) has emerged as a critical HIV reservoir. Thus, interventions aimed at controlling and eliminating HIV must include CNS-targeted strategies. Given the inaccessibility of the brain, efforts have focused on cerebrospinal fluid (CSF), aimed at defining biomarkers of HIV-disease in the CNS, including HIV-specific antibodies. However, how antibodies traffic between the blood and CNS, and whether specific antibody profiles track with HIV-associated neurocognitive disorders (HAND) remains unclear. Here, we comprehensively profiled HIV-specific antibodies across plasma and CSF from 20 antiretroviral therapy (ART) naive or treated persons with HIV. CSF was populated by IgG1 and IgG3 antibodies, with reduced Fc-effector profiles. While ART improved plasma antibody functional coordination, CSF profiles were unaffected by ART and were unrelated to HAND severity. These data point to a functional sieving of antibodies across the blood-brain barrier, providing previously unappreciated insights for the development of next-generation therapeutics targeting the CNS reservoir.

Unsuppressed viral load after intensive adherence counselling in rural eastern Uganda; a case of Kamuli district, Uganda

BACKGROUND

The East Central (EC) region of Uganda has the least viral suppression rate despite having a relatively low prevalence of human immunodeficiency virus (HIV). Although the viral suppression rate in Kamuli district is higher than that observed in some of the districts in the region, the district has one of the largest populations of people living with HIV (PLHIV). We sought to examine the factors associated with viral suppression after the provision of intensive adherence counselling (IAC) among PLHIV in the district.

METHODS

We reviewed records of PLHIV and used them to construct a retrospective cohort of patients that started and completed IAC during January - December 2019 at three high volume HIV treatment facilities in Kamuli district. We also conducted key informant interviews of focal persons at the study sites. We summarized the data descriptively, tested differences in the outcome (viral suppression after IAC) using chi-square and t-tests, and established independently associated factors using log-binomial regression analysis with robust standard errors at 5% statistical significance level using STATA version 15.

RESULTS

We reviewed 283 records of PLHIV. The mean age of the participants was 35.06 (SD 18.36) years. The majority of the participants were female (56.89%, 161/283). The viral suppression rate after IAC was 74.20% (210/283). The most frequent barriers to ART adherence reported were forgetfulness 166 (58.66%) and changes in the daily routine 130 (45.94). At multivariable analysis, participants that had a pre-IAC viral load that was greater than 2000 copies/ml [adjusted Prevalence Risk Ratio (aPRR)= 0.81 (0.70 - 0.93), p=0.002] and those that had a previous history of viral load un-suppression [aPRR= 0.79 (0.66 - 0.94), p=0.007] were less likely to achieve a suppressed viral load after IAC. ART drug shortages were rare, ART clinic working hours were convenient for clients and ART clinic staff received training in IAC.

CONCLUSION

Despite the consistency in drug availability, counselling training, flexible and frequent ART clinic days, the viral suppression rate after IAC did not meet recommended targets. A high viral load before IAC and a viral rebound were independently associated with having an unsuppressed viral load after IAC. IAC alone may not be enough to achieve viral suppression among PLHIV. To improve viral suppression rates after IAC, other complementary services should be paired with IAC.

Heavy Alcohol Use is Associated with Lower CD4 Counts among Russian Women Living with HIV: A Multilevel Analysis

Alcohol use remains prevalent among Russian women with HIV infection. Multilevel mixed effects models were used to estimate the association of heavy drinking and HIV outcomes among women (N = 250 at baseline; N = 207 at follow-up), aged 18-35, engaged in HIV care in Saint Petersburg. Alcohol use was assessed at baseline and 3 months by self-report and by the biomarker phosphatidylethanol (PEth). Overall, 35% of women were heavy drinkers, defined as women reporting ≥ 1 past-30-day heavy drinking episode (≥ 4 standard drinks on one occasion) or with PEth blood levels ≥ 80 ng/mL. Women who engaged in heavy drinking had an average 41 CD4 cells/mm³ (95% CI = - 81, - 2; z = - 2.04; P = 0.042) fewer than those who did not. Heavy drinking was associated with higher HIV symptom burden (IRR = 1.20; 95% CI = 1.05, 1.36; z = 2.73; P = 0.006) and suboptimal antiretroviral adherence (OR = 3.04; 95% CI = 1.27, 7.28; χ² = 2.50; P = 0.013), but not with viral load. Findings support the integration of alcohol treatment interventions as part of routine HIV care in Russia.

Modest de novo Reactivation of Single HIV-1 Proviruses in Peripheral CD4+ T Cells by Romidepsin

A cure for human immunodeficiency virus (HIV-1) is restricted by the continued presence of a latent reservoir of memory CD4+ T cells with proviruses integrated into their DNA despite suppressive antiretroviral therapy (ART). A predominant strategy currently pursued in HIV-1 cure-related research is the “kick and kill” approach, where latency reversal agents (LRAs) are used to reactivate transcription from integrated proviruses. The premise of this approach is that “kicking” latent virus out of hiding allows the host immune system to recognize and kill infected cells. Clinical trials investigating the efficacy of LRAs, such as romidepsin, have shown that these interventions do induce transient spikes in viral RNA in HIV-1-infected individuals. However, since these trials failed to significantly reduce viral reservoir size or significantly delay time to viral rebound during analytical treatment interruptions, it is questioned how much each individual latent provirus is actually “kicked” to produce viral transcripts and/or proteins by the LRA. Here, we developed sensitive and specific digital droplet PCR-based assays with single-provirus level resolution. Combining these assays allowed us to interrogate the level of viral RNA transcripts from single proviruses in individuals on suppressive ART with or without concomitant romidepsin treatment. Small numbers of proviruses in peripheral blood memory CD4+ T cells were triggered to become marginally transcriptionally active upon romidepsin treatment. These novel assays can be applied retrospectively and prospectively in HIV-1 cure-related clinical trials to gain crucial insights into LRA efficacy at the single provirus level.

Sexually transmitted infections among HIV serodiscordant partners: A secondary analysis of HIV Prevention Trial Network 052

Sexually transmitted infections (STIs) remain a public health concern because of their interaction(s) with HIV. In the HPTN 052 study, STIs were evaluated in both HIV-positive index cases and their HIV-negative partners at enrollment and at yearly follow-up visits. Our definition for STI was based on any infection with Chlamydia trachomatis, Neisseria gonorrhoeae, syphilis, or Trichomonas vaginalis. We used log-binomial regression models to identify factors associated with prevalent STIs. Generalized estimating equation models with the Poisson distribution were used to compare STI incidence between HIV-positive index cases and HIV-negative partners. 8.1% of the participants had STIs at enrollment. The prevalence of STIs (8.9 vs. 7.2) was higher in HIV-positive index cases than HIV-negative partners. Being female (prevalence ratio (PR) = 1.61; 95% CI: 1.20-2.16) or unmarried (PR = 1.92; 95% CI: 1.17-3.14) was associated with prevalent STIs. Compared to HIV-negative male partners, HIV-positive female index cases had a higher risk of STI acquisition (incidence rate ratio (IRR) = 2.25; 95% CI: 1.70-2.97). While we are implementing HIV prevention interventions for HIV-negative people, we should also intensify targeted STI prevention interventions, especially among HIV-positive women.

Effects of Urethritis on HIV in Semen: Implications for HIV Prevention and Cure

BACKGROUND

Prior to the widespread availability of antiretroviral therapy (ART), Men living with HIV with urethritis had increased concentration of HIV in semen. This study aims to better evaluate HIV shedding in men with urethritis receiving ART, and implications for the cure of HIV.

METHODS

Men living with HIV with urethritis taking ART ≥12 weeks were enrolled at a sexually transmitted infections clinic in Lilongwe, Malawi. Study follow-up included visits 1, 2, 4, 8, 12, 24, 36, and 48 weeks post urethritis diagnosis and treatment. Matched blood and semen samples were collected at all visits, and all additional episodes of urethritis were followed with extra visits 1, 2, and 4 weeks after treatment.

RESULTS

111 men enrolled in the study between January 2017 - March 2019, and 77 (69%) were suppressed in the blood (<400 copies/mL). Among the 77 men, 87 episodes of urethritis were evaluated during follow-up. Of the 87 episodes, 15 episodes (17%) had instances of seminal viral shedding ≥400 copies/mL despite viral suppression in the blood. At follow-up of non-urethritis episodes, ≤6% of men at each visit had a viral load ≥400 copies/mL in the semen while maintaining viral suppression in the blood.

CONCLUSIONS

An HIV cure requires the elimination of HIV from every body compartment, but available ART does not currently accomplish this. Our study highlights the male genital tract as a local source of HIV that can be reversibly activated. A better understanding of this phenomenon is important to advance the HIV cure field.

Reduced Time to Suppression Among Neonates With HIV Initiating Antiretroviral Therapy Within 7 Days After Birth

There are limited data on infants with HIV starting antiretroviral therapy (ART) in the neonatal period. We investigated the association between the timing of ART initiation and time-to-suppression among infants who tested HIV-positive and initiated ART within the first 28 days of life. The effect was estimated using cumulative probability flexible parametric spline models and a multivariable generalized additive mixed model was performed to test nonlinear associations. Forty-four neonates were included. Nineteen (43.2%) initiated ART within 7 days of life and 25 (56.8%) from 8 to 28 days. Infants treated within 7 days were 4-fold more likely to suppress earlier than those treated after 7 days [Hazard ratio (HR) 4.01 (1.7-9.5)]. For each week the ART initiation was delayed, the probability of suppression decreased by 35% (HR 0.65 [0.46-0.92]). Age at ART start was linearly associated with time-to-suppression. However, a linear association with normally distributed residuals was not found between baseline viral load and time-to-suppression, with no association found when baseline viral loads were ≤5 log(10) copies/mL, but with exponential increase in time-to-suppression with > log5 copies/mL at baseline. Starting ART within 7 days of life led to 4-fold faster time to viral suppression, in comparison to initiation from 8 to 28 days.

The effect of "universal test and treat" program on HIV treatment outcomes and patient survival among a cohort of adults taking antiretroviral treatment (ART) in low income settings of Gurage zone, South Ethiopia

BACKGROUND

Through universal "test and treat approach" (UTT) it is believed that HIV new infection and AIDS related death will be reduced at community level and through time HIV can be eliminated. With this assumption the UTT program was implemented since 2016. However, the effect of this program in terms of individual patient survival and treatment outcome was not assessed in relation to the pre-existing defer treatment approach.

OBJECTIVE

To assess the effects of UTT program on HIV treatment outcomes and patient survival among a cohort of adult HIV infected patients taking antiretroviral treatment in Gurage zone health facilities.

METHODS

Institution based retrospective cohort study was conducted in facilities providing HIV care and treatment. Eight years (2012-2019) HIV/AIDS treatment records were included in the study. Five hundred HIV/AIDS treatment records were randomly selected and reviewed. Data were abstracted using standardized checklist by trained health professionals; then it was cleaned, edited and entered by Epi info version 7 and analyzed by STATA. Cox model was built to estimate survival differences across different study variables.

RESULTS

A total of 500 patients were followed for 1632.6 person-year (PY) of observation. The overall incidence density rate (IDR) of death in the cohort was 3 per-100-PY. It was significantly higher for differed treatment program, which is 3.8 per-100-PY compared to 2.4 per-100-PY in UTT program with a p value of 0.001. The relative risk of death among differed cases was 1.58 times higher than the UTT cases. The cumulative probability of survival at the end of 1st, 2nd, 3rd, and 4th years was 98%, 90.2%, 89.2% and 88% respectively with difference between groups. The log rank test and Kaplan-Meier survival curve indicated patients enrolled in the UTT program survived longer than patients enrolled in the differed treatment program (log rank X2 test = 4.1, p value = 0.04). Age, residence, base line CD4 count, program of enrolment, development of new OIS and treatment failure were predicted mortality from HIV infection.

CONCLUSION

Mortality was significantly reduced after UTT. Therefore, intervention to further reduce deaths has to focus on early initiation of treatment and strengthening UTT programs.

People with high HIV viral load within risk networks: who are these people and who refers them best?

Introduction:

Viral load is one of the most important determinants for HIV transmission. Identification of people with high viral load (PHVL) can be effective in limiting onward HIV transmission. In order to improve the identification of these individuals within risk networks, we determined a) the number of PHVL recruited through risk networks b) their socio-demographic, behavioural and clinical characteristics and c) the characteristics of individuals who referred these PHVL to the study.

Methodology:

From November 2013 to March 2016, in Odessa, Ukraine, Transmission Reduction Intervention Project (TRIP) was implemented to identify people recently infected with HIV within the risk networks of “seeds” and “venues” where they engaged in risk behaviour.

Results:

TRIP identified 53 PHVL, of whom 32 (60%) injected drugs; 42 (79%) were unaware of their HIV status; 25 (47%) had more than one sex partner, and only 14 (26%) were using condoms. There were 164 people who referred individuals into the study; 33 of them (20%) referred PHVL. In terms of referrers, those with lower than secondary level of education, not living with a sex partner, and reporting regular condom use were significantly more likely (p < 0.05) to refer PHVL. Most PHVL (38, 72%) and their referrers (27, 82%) were found through venues.

Conclusions:

In Odessa city, PHVL are at high risk of transmitting HIV as the majority inject drugs, do not know their HIV status, and have unprotected sex and/or multiple partners. Targeting these individuals for HIV prevention, harm reduction and initiation of antiretroviral treatment (ART) is urgent.

Ethnicity as predictor of immune reconstitution among Malaysian HIV-positive patients treated with highly active antiretroviral therapy

The impact of sociodemographic and clinical factors on immune recovery and viral load suppression among HIV-1 positive patients treated with HAART particularly in Malaysia is largely unknown. This cross-sectional study enrolled 170 HIV-1-infected individuals of three major ethnicities who attended three HIV outpatient clinics in Malaysia. Questionnaire was used to obtain sociodemographic data while CD4 count and viral load data were gathered from hospital's record. Multiple factors were assessed for their predictive effects on CD4 count recovery (≥500 cells/mm³ ) and viral load suppression (≤50 copies/mL) using binary logistic regression. Most of the subjects were male (149/87.6%), in the age group 30 to 39 years old (78/45.9%) and got infected via homosexual contact (82/48.2%). Indians were associated with 11 times higher chance for CD4 recovery as compared to Malays at 8 to 12 months of HAART (adjusted OR: 10.948, 95% CI: 1.873, 64.001, P = .008). Viral load suppression was positively influenced by intravenous drug use (IVDU) status (adjusted OR: 35.224, 95% CI: 1.234, 1000.489, P = .037) at 4 to 6 months of HAART. Higher pretreatment CD4 count was a positive predictor for both initial immunological and virological responses while higher pretreatment viral load was a negative predictor for virological suppression only. In conclusion, ethnicity plays a significant role in determining early immune reconstitution in Malaysia, besides pretreatment CD4 count. Further studies are needed to identify possible biological factors underlying this association.

The Impact of ACA and Medicaid Expansion on Progress Toward UNAIDS 90-90-90 Goals

PURPOSE OF REVIEW

Passage of the Affordable Care Act (ACA) in 2010 and subsequent Medicaid expansion has influenced access to HIV treatment and care in the USA. This review aims to evaluate whether the implementation of these policies has impacted progress toward UNAIDS 90-90-90 goals.

RECENT FINDINGS

Preliminary evidence has emerged suggesting that the ACA and Medicaid expansion has increased the likelihood of HIV testing and diagnosis, reduced the number of people unaware of HIV infection, and increased the number of people on antiretroviral therapy (ART) who are virally suppressed. While the ACA is associated with some progress toward 90-90-90 goals, more years of data after policy implementation are needed for robust analysis. Methods including difference-in-differences, instrumental variables, and propensity scores are recommended to minimize bias from unmeasured confounders and make causal inference about non-random Medicaid expansion among states.

Presentation to HIV care and antiretroviral therapy initiation and response in clinical practice from 2003 through 2013

Universal HIV screening and treatment initiation of HIV-positive persons are well-established standards. However, late presentation to care is a barrier to early antiretroviral therapy (ART) and prevention of HIV transmission. We sought to determine the immunodeficiency at presentation to care and characterize the initiation and response to ART among HIV-positive persons over 2003–2013 in our urban HIV clinical practice at the Cleveland Clinic. Using a retrospective cohort study design, we assessed the CD4 cell count of HIV-positive patients at entry into care for each year and evaluated the trend over time. For patients who initiated treatment, we assessed the pretreatment CD4 cell count, consistency of timing and regimen with US treatment guidelines, and HIV RNA level at one-year and last follow-up visits. Regression analyses were used to determine predictors of study outcomes. We found that the cohort (N = 452) median CD4 cell count at presentation to care was 297 cells/mm3 (inter-quartile range: 104–479 cells/mm3), without any significant change over time (P = 0.62), and with 37% and 21% of presentations being late and advanced, respectively. Guideline-consistency (85%–100%) and regimen-consistency (41%–100%) were moderate to high and improved over time. Virologic suppression (<400 copies/ml) at one year and last follow-up was high (79% and 92%) and associated with regimen selection and durability. We conclude that CD4 cell count at first presentation to HIV care remained less than 350 cells/mm3 for 11 years in our clinical practice, despite advances in HIV testing and treatment guidelines. Early diagnosis and linkage to care and treatment are critical for ending the HIV epidemic.

Healthcare facility characteristics associated with achievement and maintenance of HIV viral suppression among persons newly diagnosed with HIV in New York City

Health care facility characteristics have been shown to influence intermediary health outcomes among persons with HIV, but few longitudinal studies of suppression have included these characteristics. We studied the association of these characteristics with the achievement and maintenance of HIV viral suppression among New York City (NYC) residents aged 13 years and older newly diagnosed with HIV between 2006 and 2012. The NYC HIV surveillance registry provided individual and facility data (N = 12,547 persons). Multivariable proportional hazards models estimated the likelihood of individual achievement and maintenance of suppression by type of facility, patient volume, and distance from residence, accounting for facility clustering and for individual-level confounders. Viral suppression was achieved within 12 months by 44% and at a later point by another 29%. Viral suppression occurred at a lower rate in facilities with low HIV patient volume (e.g., 10-24 diagnoses per year vs. ≥75, adjusted hazard ratio [AHR] = 0.87, 95% confidence interval [CI] 0.79-0.95) and in screening/diagnosis sites (vs. hospitals, AHR = 0.86, 95% CI 0.80-0.92). Among persons achieving viral suppression, 18% experienced virologic failure within 12 months and 24% later. Those receiving care at large outpatient facilities or large private practices had a lower rate of virologic failure (e.g., large outpatient facilities vs. large hospitals, AHR = 0.63, 95% CI 0.53-0.75). Achievement and maintenance of viral suppression were associated with facilities with higher HIV-positive caseloads. Some facilities with small caseloads and screening/diagnosis sites may need stronger care or referral systems to help persons with HIV achieve and maintain viral suppression.

Schistosomiasis and HIV-1 viral load in HIV-infected outpatients with immunological failure in Tanzania: a case-control study

Background

Schistosoma sp. infection has been shown to interact with HIV-1 by modifying susceptibility to the virus and impacting AIDS outcome, but very little is known about the potential impact of Schistosoma sp. infection on the efficiency of antiretroviral treatment (ART) in HIV-1 infected individuals. One study suggested increased immunological failure in patients infected with schistosomes compared to those uninfected. To our knowledge, no report exists on the virological response to ART in schistosome-infected individuals. In addition, viral load in HIV-1 infected individuals changes over the course of the HIV infection. This study assessed the impact of HIV-1/Schistosoma sp. co-infections on viral load in people with immunological failure on ART, taking into account the duration of HIV-1 infection.

Methods

We enrolled HIV-1 infected Tanzanian adults over 18 years of age who had used first line ART for more than 6 months and were identified to have immunological failure by the WHO criteria (50% drop from peak CD4 count, or CD4 count equal to or below baseline after 6 months of ART, or CD4 count below 100cells/mm³ after 1 year of ART). Patients were also tested for schistosome infection by microscopy for ova in urine and stool and by circulating anodic antigen (CAA) levels in serum. The duration of HIV-1 infection was calculated using baseline CD4+ T-cell (CD4) counts determined at enrollment. Univariable and multivariable analyses were conducted to compare viral loads in schistosome infected and uninfected patients.

Results

A total of 188 patients were enrolled. After univariable analysis, female sex, lower peak CD4 counts, lower current CD4 counts, anemia, and shorter time infected with HIV-1 were all significantly associated with higher viral load. Schistosome infection was not associated with viral load even after adjusting for sex, current CD4 counts and duration of HIV-1 infection.

Conclusions

The current study of HIV-infected patients with immunological failure on ART suggests that once ART is introduced, ART is the dominant driver of viral load and schistosome infection may no longer have an impact.

A superiority of viral load over CD4 cell count when predicting mortality in HIV patients on therapy

Background

CD4 cell count has been identified to be an essential component in monitoring HIV treatment outcome. However, CD4 cell count monitoring sometimes fails to predict virological failure resulting in unnecessary switch of treatment lines which causes drug resistance and limitations of treatment options. This study assesses the use of both viral load (HIV RNA) and CD4 cell count in the monitoring of HIV/AIDS progression.

Methods

Time-homogeneous Markov models were fitted, one on CD4 cell count monitoring and the other on HIV RNA monitoring. Effects of covariates; gender, age, CD4 baseline, HIV RNA baseline and adherence to treatment were assessed for each of the fitted models. Assessment of the fitted models was done using prevalence plots and the likelihood ratio tests. The analysis was done using the “msm” package in R.

Results

Results from the analysis show that viral load monitoring predicts deaths of HIV/AIDS patients better than CD4 cell count monitoring. Assessment of the fitted models shows that viral load monitoring is a better predictor of HIV/AIDS progression than CD4 cell count.

Conclusion

From this study one can conclude that although patients take more time to achieve a normal CD4 cell count and less time to achieve an undetectable viral load, once the CD4 cell count is normal, mortality risks are reduced. Therefore, both viral load monitoring and CD4 count monitoring can be used to provide useful information which can be used to improve life expectance of patients living with HIV. However, viral load monitoring is a better predictor of HIV/AIDS progression than CD4 cell count and hence viral load is deemed superior.

Electronic supplementary material

The online version of this article (10.1186/s12879-019-3781-1) contains supplementary material, which is available to authorized users.

Racial Disparities in Virologic Failure and Tolerability During Firstline HIV Antiretroviral Therapy

BACKGROUND

Racial/ethnic disparities in HIV outcomes have persisted despite effective antiretroviral therapy. In a study of initial regimens, we found viral suppression varied by race/ethnicity. In this exploratory analysis, we use clinical and socioeconomic data to assess factors associated with virologic failure and adverse events within racial/ethnic groups.

METHODS

Data were from AIDS Clinical Trial Group A5257, a randomized trial of initial regimens with either atazanavir/ritonavir, darunavir/ritonavir, or raltegravir (each combined with tenofovir DF and emtricitabine). We grouped participants by race/ethnicity and then used Cox-proportional hazards regression to examine the impact of demographic, clinical, and socioeconomic factors on the time to virologic suppression and time to adverse event reporting within each racial/ethnic group.

RESULTS

We analyzed data from 1762 participants: 757 self-reported as non-Hispanic black (NHB), 615 as non-Hispanic white (NHW), and 390 as Hispanic. The proportion with virologic failure was higher for NHB (22%) and Hispanic (17%) participants compared with NHWs (9%). Factors associated with virologic failure were poor adherence and higher baseline HIV RNA level. Prior clinical AIDS diagnosis was associated with virologic failure for NHBs only, and unstable housing and illicit drug use for NHWs only. Factors associated with adverse events were female sex in all groups and concurrent use of medications for comorbidities in NHB and Hispanic participants only.

CONCLUSIONS

Clinical and socioeconomic factors that are associated with virologic failure and tolerability of antiretroviral therapy vary between and within racial and ethnic groups. Further research may shed light into mechanisms leading to disparities and targeted strategies to eliminate those disparities.

Assessment of the 24th Week Success of Anti-Retroviral Therapy in the Action against HIV in Istanbul Database: Results from a Region with Increasing Incidence

We aimed to assess the 24-week virological and immunological success of the treatment of treatment-naive and treatment-experienced patients included in the Action against HIV in Istanbul (ACTHIV-IST) database. The ACTHIV-IST database was screened retrospectively from January 2012 to January 2014. The data for these patients such as age, sex, treatment-naive or treatment-experienced status, date of diagnosis, date of commencing antiretroviral therapy, antiretroviral therapy regimen, CD4+ cell count, and viral load before and after therapy were analyzed. In the 24th week of antiretroviral therapy, there were 40 (17.9%) and 29 (14.1%) virological and immunological failures, respectively. Virological failure (VF) was associated with a baseline viral load > 100,000 copies (p = 0.004). A CD4+ cell count lower than 200 cells/μl was not found to be associated with VF (p = 0.843). Immunological failure was substantially rare in patients with a baseline CD4+ cell count > 200 cells/μl (p = 0.005). Although an HIV-RNA ≤ 100,000 copies/ml was protective against VF in the 24th week, in individuals with an HIV-RNA > 100,000 copies/ml, VF was 3.2 times more likely to occur. Baseline VF was the most predictive parameter to estimate 24th week virological success and VF. VF is an important prognostic parameter resulting in CD4+ cell depletion, AIDS-related events, and increased mortality.

Impact of baseline plasma HIV-1 RNA and time to virological suppression on virological rebound according to first-line antiretroviral regimen

Objectives

We investigated the risk of virological rebound in HIV-1-infected patients achieving virological suppression on first-line combined ART (cART) according to baseline HIV-1 RNA, time to virological suppression and type of regimen.

Patients and methods

Subjects were 10 836 adults who initiated first-line cART (two nucleoside or nucleotide reverse transcriptase inhibitors + efavirenz, a ritonavir-boosted protease inhibitor or an integrase inhibitor) from 1 January 2007 to 31 December 2014. Cox proportional hazards models with multiple adjustment and propensity score matching were used to investigate the effect of baseline HIV-1 RNA and time to virological suppression on the occurrence of virological rebound.

Results

During 411 436 patient-months of follow-up, risk of virological rebound was higher in patients with baseline HIV-1 RNA ≥100 000 copies/mL versus <100 000 copies/mL, in those achieving virological suppression in > 6 months versus <6 months, and lower with efavirenz or integrase inhibitors than with ritonavir-boosted protease inhibitors. Baseline HIV-1 RNA >100 000 copies/mL was associated with virological rebound for ritonavir-boosted protease inhibitors but not for efavirenz or integrase inhibitors. Time to virological suppression >6 months was strongly associated with virological rebound for all regimens.

Conclusions

In HIV-1-infected patients starting cART, risk of virological rebound was lower with efavirenz or integrase inhibitors than with ritonavir-boosted protease inhibitors. These data, from a very large observational cohort, in addition to the more rapid initial virological suppression obtained with integrase inhibitors, reinforce the positioning of this class as the preferred one for first-line therapy.

Optimizing prevention of HIV mother to child transmission: Duration of antiretroviral therapy and viral suppression at delivery among pregnant Malawian women

Background

Effective antiretroviral therapy during pregnancy minimizes the risk of vertical HIV transmission. Some women present late in their pregnancy for first antenatal visit; whether these women achieve viral suppression by delivery and how suppression varies with time on ART is unclear.

Methods

We conducted a prospective cohort study of HIV-infected pregnant women initiating antiretroviral therapy for the first time at Bwaila Hospital in Lilongwe, Malawi from June 2015 to November 2016. Multivariable Poisson models with robust variance estimators were used to estimate risk ratios (RR) and 95% confidence intervals (CI) of the association between duration of ART and both viral load (VL) ≥1000 copies/ml and VL ≥40 copies/ml at delivery.

Results

Of the 252 women who had viral load testing at delivery, 40 (16%) and 78 (31%) had VL ≥1000 copies/ml and VL ≥40 copies/ml, respectively. The proportion of women with poor adherence to ART was higher among women who were on ART for ≤12 weeks (9/50 = 18.0%) than among those who were on ART for 13–35 weeks (18/194 = 9.3%). Compared to women who were on ART for ≤12 weeks, women who were on ART for 13–20 weeks (RR = 0.52; 95% CI: 0.36–0.74) or 21–35 weeks (RR = 0.26; 95% CI: 0.14–0.48) had a lower risk of VL ≥40 copies/ml at delivery. Similar comparisons for VL ≥1000 copies/ml at delivery showed decrease in risk although not significant for those on ART 13–20 weeks.

Conclusion

Longer duration of ART during pregnancy was associated with suppressed viral load at delivery. Early ANC attendance in pregnancy to facilitate prompt ART initiation for HIV-positive women is essential in the effort to eliminate HIV vertical transmission.

Time-homogeneous Markov process for HIV/AIDS progression under a combination treatment therapy: cohort study, South Africa

BACKGROUND

As HIV enters the human body, its main target is the CD4 cell which it turns into a factory that produces millions of other HIV particles. These HIV particles target new CD4 cells resulting in the progression of HIV infection to AIDS. A continuous depletion of CD4 cells results in opportunistic infections, for example tuberculosis (TB). The purpose of this study is to model and describe the progression of HIV/AIDS disease in an individual on antiretroviral therapy (ART) follow up using a continuous time homogeneous Markov process. A cohort of 319 HIV infected patients on ART follow up at a Wellness Clinic in Bela Bela, South Africa is used in this study. Though Markov models based on CD4 cell counts is a common approach in HIV/AIDS modelling, this paper is unique clinically in that tuberculosis (TB) co-infection is included as a covariate.

METHODS

The method partitions the HIV infection period into five CD4-cell count intervals followed by the end points; death, and withdrawal from study. The effectiveness of treatment is analysed by comparing the forward transitions with the backward transitions. The effects of reaction to treatment, TB co-infection, gender and age on the transition rates are also examined. The developed models give very good fit to the data.

RESULTS

The results show that the strongest predictor of transition from a state of CD4 cell count greater than 750 to a state of CD4 between 500 and 750 is a negative reaction to drug therapy. Development of TB during the course of treatment is the greatest predictor of transitions to states of lower CD4 cell count. Transitions from good states to bad states are higher on male patients than their female counterparts. Patients in the cohort spend a greater proportion of their total follow-up time in higher CD4 states.

CONCLUSION

From some of these findings we conclude that there is need to monitor adverse reaction to drugs more frequently, screen HIV/AIDS patients for any signs and symptoms of TB and check for factors that may explain gender differences further.

Neighborhood Characteristics Associated with Achievement and Maintenance of HIV Viral Suppression Among Persons Newly Diagnosed with HIV in New York City

We investigated the effect of neighborhood characteristics on achievement and maintenance of HIV viral suppression among New York City (NYC) residents aged 13 years and older diagnosed between 2006 and 2012. Individual records from the NYC HIV surveillance registry (n = 12,547) were linked to U.S. Census and American Community Survey data by census tract of residence. Multivariable proportional hazards regression models indicated the likelihood of achievement and maintenance of suppression by neighborhood characteristics including poverty, accounting for neighborhood clustering and for individual characteristics. In adjusted analyses, no neighborhood factors were associated with achievement of suppression. However, residents of high- or very-high-poverty neighborhoods were less likely than residents of low-poverty neighborhoods to maintain suppression. In conclusion, higher neighborhood poverty was associated with lesser maintenance of suppression. Assistance with post-diagnosis retention in care, antiretroviral therapy prescribing, or adherence targeted to residents of higher-poverty neighborhoods may improve maintenance of viral suppression in NYC.

Using Participatory System Dynamics Modeling to Examine the Local HIV Test and Treatment Care Continuum in Order to Reduce Community Viral Load

Achieving community-level goals to eliminate the HIV epidemic requires coordinated efforts through community consortia with a common purpose to examine and critique their own HIV testing and treatment (T&T) care system and build effective tools to guide their efforts to improve it. Participatory system dynamics (SD) modeling offers conceptual, methodological, and analytical tools to engage diverse stakeholders in systems conceptualization and visual mapping of dynamics that undermine community-level health outcomes and identify those that can be leveraged for systems improvement. We recruited and engaged a 25-member multi-stakeholder Task Force, whose members provide or utilize HIV-related services, to participate in SD modeling to examine and address problems of their local HIV T&T service system. Findings from the iterative model building sessions indicated Task Force members' increasingly complex understanding of the local HIV care system and demonstrated their improved capacity to visualize and critique multiple models of the HIV T&T service system and identify areas of potential leverage. Findings also showed members' enhanced communication and consensus in seeking deeper systems understanding and options for solutions. We discuss implications of using these visual SD models for subsequent simulation modeling of the T&T system and for other community applications to improve system effectiveness.

Virologic outcomes in early antiretroviral treatment: HPTN 052

INTRODUCTION

The HIV Prevention Trials Network (HPTN) 052 trial demonstrated that early antiretroviral therapy (ART) prevented 93% of HIV transmission events in serodiscordant couples. Some linked infections were observed shortly after ART initiation or after virologic failure.

OBJECTIVE

To evaluate factors associated with time to viral suppression and virologic failure in participants who initiated ART in HPTN 052.

METHODS

1566 participants who had a viral load (VL) > 400 copies/mL at enrollment were included in the analyses. This included 832 in the early ART arm (CD4 350-550 cells/mm³ at ART initiation) and 734 in the delayed ART arm (204 with a CD4 < 250 cells/mm³ at ART initiation; 530 with any CD4 at ART initiation). Viral suppression was defined as two consecutive VLs ≤ 400 copies/mL after ART initiation; virologic failure was defined as two consecutive VLs > 1000 copies/mL > 24 weeks after ART initiation.

RESULTS

Overall, 93% of participants achieved viral suppression by 12 months. The annual incidence of virologic failure was 3.6%. Virologic outcomes were similar in the two study arms. Longer time to viral suppression was associated with younger age, higher VL at ART initiation, and region (Africa vs. Asia). Virologic failure was strongly associated with younger age, lower educational level, and lack of suppression by three months; lower VL and higher CD4 at ART initiation were also associated with virologic failure.

CONCLUSIONS

Several clinical and demographic factors were identified that were associated with longer time to viral suppression and virologic failure. Recognition of these factors may help optimize ART for HIV treatment and prevention.

Cigarette smoking is associated with high HIV viral load among adults presenting for antiretroviral therapy in Vietnam

High HIV viral load (VL >100,000 cp/ml) is associated with increased HIV transmission risk, faster progression to AIDS, and reduced response to some antiretroviral regimens. To better understand factors associated with high VL, we examined characteristics of patients presenting for treatment in Hanoi, Vietnam. We examined baseline data from the Viral Load Monitoring in Vietnam Study, a randomized controlled trial of routine VL monitoring in a population starting antiretroviral therapy (ART) at a clinic in Hanoi. Patients with prior treatment failure or ART resistance were excluded. Characteristics examined included demographics, clinical and laboratory data, and substance use. Logistic regression was used to calculate crude and adjusted odds ratios (aOR) and 95% confidence intervals (95% CI). Out of 636 patients, 62.7% were male, 72.9% were ≥30 years old, and 28.3% had a history of drug injection. Median CD4 was 132 cells/mm3, and 34.9% were clinical stage IV. Active cigarette smoking was reported by 36.3% with 14.0% smoking >10 cigarettes per day. Alcohol consumption was reported by 20.1% with 6.1% having ≥5 drinks per event. Overall 53.0% had a VL >100,000 cp/ml. Male gender, low body weight, low CD4 count, prior TB, and cigarette smoking were associated with high VL. Those who smoked 1–10 cigarettes per day were more likely to have high VL (aOR = 1.99, 95% CI = 1.15–3.45), while the smaller number of patients who smoked >10 cigarettes per day had a non-significant trend toward higher VL (aOR = 1.41, 95% CI = 0.75–2.66). Alcohol consumption was not significantly associated with high VL. Tobacco use is increasingly recognized as a contributor to premature morbidity and mortality among HIV-infected patients. In our study, cigarette smoking in the last 30 days was associated with a 1.5 to 2-fold higher odds of having an HIV VL >100,000 cp/ml among patients presenting for ART. These findings provide further evidence of the negative effects of tobacco use among HIV-infected patients.

Modelling the evolution of HIV-1 virulence in response to imperfect therapy and prophylaxis

Average HIV-1 virulence appears to have evolved in different directions in different host populations since antiretroviral therapy first became available, and models predict that HIV drugs can select for either higher or lower virulence, depending on how treatment is administered. However, HIV virulence evolution in response to "leaky" therapy (treatment that imperfectly suppresses viral replication) and the use of preventive drugs (pre-exposure prophylaxis) has not been explored. Using adaptive dynamics, we show that higher virulence can evolve when antiretroviral therapy is imperfectly effective and that this evolution erodes some of the long-term clinical and epidemiological benefits of HIV treatment. The introduction of pre-exposure prophylaxis greatly reduces infection prevalence, but can further amplify virulence evolution when it, too, is leaky. Increasing the uptake rate of these imperfect interventions increases selection for higher virulence and can lead to counterintuitive increases in infection prevalence in some scenarios. Although populations almost always fare better with access to interventions than without, untreated individuals could experience particularly poor clinical outcomes when virulence evolves. These findings predict that antiretroviral drugs may have underappreciated evolutionary consequences, but that maximizing drug efficacy can prevent this evolutionary response. We suggest that HIV virulence evolution should be closely monitored as access to interventions continues to improve.

Odds of Viral Suppression by Single-Tablet Regimens, Multiple-Tablet Regimens, and Adherence Level in HIV/AIDS Patients Receiving Antiretroviral Therapy

STUDY OBJECTIVE

To evaluate the odds of achieving viral suppression in human immunodeficiency virus (HIV) patients using antiretroviral therapy as a single-tablet regimen (STR) or multiple-tablet regimen (MTR).

DESIGN

Retrospective cohort study.

DATA SOURCES

South Carolina Medicaid medical and pharmacy paid claims data were obtained from the South Carolina Revenue and Fiscal Affairs Office; laboratory data were obtained from the South Carolina Department of Health and Environmental Control.

PATIENTS

A total of 1536 patients who were dispensed a complete STR (477 patients) or MTR (1059 patients) regimen lasting at least 60 days between January 1, 2006, and December 31, 2013.

MEASUREMENTS AND MAIN RESULTS

The analysis examined adherence levels and regimen type on odds of viral load suppression. Regimen adherence levels (90-94%, 85-89%, 80-84%, and less than 80%) were compared with the gold standard adherence for HIV of 95% or greater. Patients were followed from index date until the earliest date of regimen discontinuation, treatment switch, end of study period, last date of eligibility, or death. Differences in outcomes were evaluated by χ² , Wilcoxon rank sum statistical tests, and multivariate regression models controlling for covariates. For STR regimens we find that, when compared with 95% or greater adherence, there is no statistical difference in the odds of viral suppression with adherence levels greater than or equal to 80%. However, adherence levels greater than or equal to 95% were associated with a greater odds of viral suppression when compared with less than 80% STR adherence (odds ratio [OR] 2.57, Dunnett 95% confidence interval [CI] 1.04-6.32). For MTR regimens, there was no statistical difference in the odds of viral suppression for the adherence level 90-94% compared with the 95% or greater adherence (OR 3.59, Dunnett 95% CI 0.805-16.043). However, the 95% or greater adherence has greater odds of viral suppression compared with all other MTR adherence levels. In addition, no difference was found in the odds of viral suppression between STR and MTR for all adherence levels.

CONCLUSIONS

Compared with 95% or greater adherence, STR regimens achieve viral suppression with adherence levels of 80% or greater, whereas MTR regimens require adherence levels of 90% or greater to achieve viral suppression in South Carolina Medicaid patients with HIV/AIDS.

Nonhuman Primate Models for Studies of AIDS Virus Persistence During Suppressive Combination Antiretroviral Therapy

Nonhuman primate (NHP) models of AIDS represent a potentially powerful component of the effort to understand in vivo sources of AIDS virus that persist in the setting of suppressive combination antiretroviral therapy (cART) and to develop and evaluate novel strategies for more definitive treatment of HIV infection (i.e., viral eradication "cure", or sustained off-cART remission). Multiple different NHP models are available, each characterized by a particular NHP species, infecting virus, and cART regimen, and each with a distinct capacity to recapitulate different aspects of HIV infection. Given these different biological characteristics, and their associated strengths and limitations, different models may be preferred to address different questions pertaining to virus persistence and cure research, or to evaluate different candidate intervention approaches. Recent developments in improved cART regimens for use in NHPs, new viruses, a wider array of sensitive virologic assay approaches, and a better understanding of pathogenesis should allow even greater contributions from NHP models to this important area of HIV research in the future.

Elevated CD8 T-cell counts and virological failure in HIV-infected patients after combination antiretroviral therapy

Elevated CD8 counts with combination antiretroviral therapy (cART) initiation may be an early warning indicator for future treatment failure. Thus, we investigated whether elevated CD8 counts were associated with virological failure (VF) in the first 4 years of cART in Asian HIV-infected patients in a multicenter regional cohort.We included patients from the TREAT Asia HIV Observational Database (TAHOD). Patients were included in the analysis if they started cART between 1996 and 2013 with at least one CD8 measurement within 6 months prior to cART initiation and at least one CD8 and viral load (VL) measurement beyond 6 months after starting cART. We defined VF as VL ≥400 copies/mL after 6 months on cART. Elevated CD8 was defined as CD8 ≥1200 cells/μL. Time to VF was modeled using Cox regression analysis, stratified by site.In total, 2475 patients from 19 sites were included in this analysis, of whom 665 (27%) experienced VF in the first 4 years of cART. The overall rate of VF was 12.95 per 100 person-years. In the multivariate model, the most recent elevated CD8 was significantly associated with a greater hazard of VF (HR = 1.35, 95% CI 1.14-1.61; P = 0.001). However, the sensitivity analysis showed that time-lagged CD8 measured at least 6 months prior to our virological endpoint was not statistically significant (P = 0.420).This study indicates that the relationship between the most recent CD8 count and VF was possibly due to the CD8 cells reacting to the increase in VL rather than causing the VL increase itself. However, CD8 levels may be a useful indicator for VF in HIV-infected patients after starting cART.

Evaluating facility-based antiretroviral therapy programme effectiveness: a pilot study comparing viral load suppression and retention rates

OBJECTIVES

Increased demand for antiretroviral therapy (ART) services combined with plateaued levels of development assistance for HIV/AIDS requires that national ART programmes monitor programme effectiveness. In this pilot study, we compared commonly utilised performance metrics of 12- and 24-month retention with rates of viral load (VL) suppression at 15 health facilities in Uganda.

METHODS

Retrospective chart review from which 12- and 24-month retention rates were estimated, and parallel HIV RNA VL testing on consecutive adult patients who presented to clinics and had been on ART for a minimum of six months. Rates of VL suppression were then calculated at each facility and compared to retention rates to assess the correlation between performance metrics. Multilevel logistic regression models predicting VL suppression and 12- and 24-month retention were constructed to estimate facility effects.

RESULTS

We collected VL samples from 2961 patients and found that 88% had a VL ≤1000 copies/ml. Facility rates of VL suppression varied between 77% and 96%. When controlling for patient mix, a significant variation in facility performance persisted. Retention rates at 12 and 24 months were 91% and 79%, respectively, with a comparable facility-level variation. However, neither 12-month (ρ = 0.16) nor 24-month (ρ = -0.19) retention rates were correlated with facility rates of VL suppression.

CONCLUSIONS

Retaining patients in care and suppressing VL are both critical outcomes. Given the lack of correlation noted in this study, the utilisation of VL monitoring may be necessary to truly assess the effectiveness of health facilities delivering ART services.

High level of virological suppression among HIV-infected adults receiving combination antiretroviral therapy in Addis Ababa, Ethiopia

BACKGROUND

Plasma viral load (pVL) is a key indicator of therapeutic response in HIV-infected patients receiving combination antiretroviral therapy (cART), but is often unavailable in routine clinical care in resource-limited settings. Previous model-based simulation studies have suggested that the benefits of routine pVL monitoring among patients on first-line regimens in resource-limited settings are modest, but this needs corroboration in well-defined study populations.

METHODS

We investigated virological suppression levels and identified predictors of detectable viraemia among 870 randomly selected patients who started cART between May 2009 and April 2012 in 10 health-care facilities in Addis Ababa, Ethiopia. A total of 656 (75.4%) patients, who were alive, were retained in HIV care and receiving cART for at least 6 months provided a blood sample for pVL measurement. Predictors of detectable viraemia were identified in a multivariate logistic regression model.

RESULTS

In on-treatment analysis, 94.5% (95% CI 92.5, 96.1) of the patients achieved virological suppression below 400 copies/ml after a median (IQR) of 26 (17-35) months on cART. When patients who were lost to follow-up, dead or stopped were assumed to have had detectable viraemia, the proportion of patients with virological suppression <400 copies/ml decreased to 74.6% (95% CI 71.5%, 77.4%). Younger age, lower educational status, <95% medication adherence, lower CD4(+) T-cell count at cART initiation and/or the diagnosis of immunological failure thereafter significantly predicted detectable viraemia.

CONCLUSIONS

Virological suppression levels can be high in an established ART programme in a resource-limited setting, even without the availability of routine pVL monitoring. Efforts to improve treatment outcomes should focus on younger and illiterate patients, earlier detection of HIV-positive status and cART initiation before patients are severely immunocompromised, and improving retention in care.

Efficacy and safety of lopinavir/ritonavir-based antiretroviral therapy in HIV-1-infected subjects with advanced disease: a systematic review and meta-analysis

ABSTRACT 

Aim: We examined the literature for the efficacy, safety and tolerability of lopinavir/ritonavir (LPV/r)-based regimens in antiretroviral therapy naive HIV-1-infected subjects with advanced disease. Materials & methods: Virologic and immunologic efficacy and adverse event results from prospective, randomized controlled trials evaluating LPV/r + two nucleoside reverse transcriptase inhibitors were examined using random-effects meta-analyses. Emergence of resistance was determined using data extracted from published material. Results: Thirteen studies (including ten 96-week studies) met search criteria. Virologic responses were similar at 96 weeks between subjects with HIV-1 infection treated with LPV/r-based antiretroviral therapy when stratified by baseline HIV-1 RNA or CD4+ T-cell count; immunologic responses were similar when stratified by CD4+ T-cell count. Conclusion: Through 96 weeks of treatment, the efficacy, safety and tolerability of LPV/r-based regimens were comparable in subjects with and without advanced HIV-1 disease.

A systematic review of contemporary models of shared HIV care and HIV in primary care in high-income settings

HIV shared care is uncommon in the UK although shared care could be a beneficial model of care. We review the literature on HIV shared care to determine current practice and clinical, economic and patient satisfaction outcomes. We searched MEDLINE, EMBASE, NICE Evidence, Cochrane collaboration, Google and websites of the British HIV Association, Aidsmap, Public Health England, World Health Organization and Terrence Higgins Trust using relevant search terms in August 2014. Studies published after 2000, from healthcare settings comparable to the UK that described links between primary care and specialised HIV services were included and compared using principles of the Critical Appraisal Skills Programme and Authority, Accuracy, Coverage, Objectivity, Date, Significance frameworks. Three of the nine included models reported clinical or patient satisfaction outcomes but data collection and analyses were inadequate. None reported economic outcomes although some provided financial costings. Facilitators of shared care included robust clinical protocols, training and timely communication. Few published examples of HIV shared care exist and quality of evidence is poor. There is no consistent association with improved clinical outcomes, cost effectiveness or acceptability. Models are context specific, driven by local need, although some generalisable features could inform novel service delivery. Further evaluative research is needed to determine optimal components of shared HIV care.

Antiretroviral therapy: treatment-experienced individuals

Antiretroviral therapy (ART)-experienced individuals may choose to modify their regimens because of suboptimal virologic response, poor tolerability, convenience, or to minimize interactions with other medications or food. Constructing a new regimen for any of these reasons requires a thorough review of prior antiretroviral drug use and available drug resistance results. This article summarizes the strategies used in managing the ART-experienced individual who is considering a modification in therapy at the time of suboptimal virologic response or while virologically suppressed on a stable regimen.

Recent trends in early stage response to combination antiretroviral therapy in Australia

BACKGROUND

There have been improvements in combination antiretroviral therapy (cART) over the past 15 years. The aim of this analysis was to assess whether improvements in ART have resulted in improvements in surrogates of HIV outcome.

METHODS

Patients in the Australian HIV Observational Database who initiated treatment using mono/duo therapy prior to 1996, or using cART from 1996 onwards, were included in the analysis. Patients were stratified by era of ART initiation. Median changes in CD4(+) T-cell count and the proportion of patients with detectable HIV viral load (>400 copies/ml) were calculated over the first 4 years of treatment. Probabilities of treatment switch were estimated using the Kaplan-Meier method.

RESULTS

A total of 2,753 patients were included in the analysis: 28% initiated treatment <1996 using mono/duo therapy and 72% initiated treatment ≥1996 using cART (30% 1996-1999, 12% 2000-2003, 11% 2004-2007 and 19% ≥2008). Overall CD4(+) T-cell count response improved by later era of initiation (P<0.001), although 2000-2003 CD4(+) T-cell count response was less than that for 1996-1999 (P=0.007). The average proportion with detectable viral load from 2 to 4 years post-treatment commencement by era was: <1996 mono/duo 0.69 (0.67-0.71), 1996-1999 cART 0.29 (0.28-0.30), 2000-2003 cART 0.22 (0.20-0.24), 2004-2007 cART 0.09 (0.07-0.10) and ≥2008 cART 0.04 (0.03-0.05). Probability of treatment switch at 4 years after initiation decreased from 53% in 1996-1999 to 29% after 2008 (P<0.001).

CONCLUSIONS

Across the five time-periods examined, there have been incremental improvements for patients initiated on cART, as measured by overall response (viral load and CD4(+) T-cell count) and also increased durability of first-line ART regimens.

Early initiation of antiretroviral therapy in HIV-infected adults and adolescents: a systematic review

OBJECTIVES

The objective of this review was to update evidence on when to initiate antiretroviral therapy (ART) to inform revision of the 2013 WHO guidelines for ART in low and middle-income countries.

DESIGN

A systematic review and meta-analysis.

METHODS

We comprehensively searchescohorts. Outcomes were mortality, clinical progression, virologic failure, immunologic recover, and severe adverse events. We pooled data across studies and estimated summary effect sizes. We graded the quality of evidence from the literature for each outcome.

RESULTS

We identified 24 studies; 3 were RCTs. Studies found reduced risk of mortality [1 RCT: hazard ratio 0.77, 95% confidence interval (CI) 0.34-1.76; 13 cohorts: relative risk (RR) 0.66, 95% CI 0.55-0.79], progression to AIDS or death (2 RCTs: RR 0.48, 95% CI 0.26-0.91; 9 cohorts: RR 0.70, 95% CI 0.40-1.24) and diagnosis of a non-AIDS-defining illness (1 RCT: RR 0.14, 95% CI 0.03-0.64; 1 cohort: RR 0.47, 95% CI 0.23-0.98), and an increased risk of grade 3/4 laboratory abnormalities in patients initiating ART at at least 350 cells/μl (1 RCT: RR 1.49, 95% CI 1.25-1.77). The quality of evidence was low or very low for clinical outcomes due to few events and imprecision, and high for adverse events.

CONCLUSIONS

Our findings contributed to the evidence base for the revised 2013 WHO guidelines on ART, which recommend initiating ART at CD4 T-cell counts of 350-500 cells/μl, but not above 500 cells/μl compared to initiating it later when CD4 T-cell counts fall below 350 cells/μl.