The augmented synthetic control method in public health and biomedical research

Estimating treatment (or policy or intervention) effects on a single individual or unit has become increasingly important in health and biomedical sciences. One method to estimate these effects is the synthetic control method, which constructs a synthetic control, a weighted average of control units that best matches the treated unit's pre-treatment outcomes and other relevant covariates. The intervention's impact is then estimated by comparing the post-intervention outcomes of the treated unit and its synthetic control, which serves as a proxy for the counterfactual outcome had the treated unit not experienced the intervention. The augmented synthetic control method, a recent adaptation of the synthetic control method, relaxes some of the synthetic control method's assumptions for broader applicability. While synthetic controls have been used in a variety of fields, their use in public health and biomedical research is more recent, and newer methods such as the augmented synthetic control method are underutilized. This paper briefly describes the synthetic control method and its application, explains the augmented synthetic control method and its differences from the synthetic control method, and estimates the effects of an antimalarial initiative in Mozambique using both the synthetic control method and the augmented synthetic control method to highlight the advantages of using the augmented synthetic control method to analyze the impact of interventions implemented in a single region.

Electronic Dose Monitoring Device Patterns in Youth Living With HIV Enrolled in an Adherence Intervention Clinical Trial

INTRODUCTION

Youth living with HIV in the US have low rates of viral suppression, in part because of challenges with antiretroviral therapy adherence.

METHODS

Daily dosing in the Adolescent Medicine Trials Network for HIV/AIDS Interventions 152 study, a randomized controlled trial of a 12-week adherence intervention (triggered escalating real-time adherence intervention) for viremic youth, compared with standard of care (SOC), was measured by electronic dose monitoring (EDM) throughout 48 weeks of follow-up. EDM data collected over the first 24 weeks were used to characterize patterns of antiretroviral therapy adherence with group-based trajectory models.

RESULTS

Four trajectory groups were identified among the 85 participants included in the analysis during the intervention phase of the study: (Worst) no interaction with EDM, (Declining) initially moderate EDM-based adherence followed by steep declines, (Good) initially high EDM-based adherence with modest declines, and (Best) consistently high EDM-based adherence. Being in the SOC arm, not being in school, higher evasiveness and panic decision-making scores, and lower adherence motivation were associated with higher odds of being in a worse trajectory group ( P < 0.05). A general decline in dosing was observed in the 12 weeks postintervention, when all participants were managed using SOC.

CONCLUSIONS

Use of group-based trajectory models allowed a more nuanced understanding of EDM-based adherence over time compared with collapsed summary measures. In addition to the study intervention, other factors influencing EDM-based adherence included being in school, decision-making styles, and adherence-related motivation. This information can be used to design better intervention services for youth living with HIV.

Pilot Trial of a Critical Consciousness-Based Intervention for Black Young Gay and Bisexual Men Living with HIV: Mobilizing Our Voices for Empowerment (MOVE)

HIV in the USA disproportionately affects Black young gay and bisexual men (Y-GBM). This article presents outcomes of a pilot randomized controlled trial comparing Mobilizing our Voices for Empowerment (MOVE), a culturally and developmentally tailored critical consciousness-based intervention for Black Y-GBM living with HIV (ages 16-24), with a comparison health promotion intervention. Black Y-GBM (n = 54) from four cities participated. Mixed effects models across four assessment points revealed participants in MOVE showed greater increases over time in perceived stress of HIV disclosure, self-efficacy for limiting HIV risk behavior, and condom use self-efficacy. Examining mean difference scores separately, participants in MOVE demonstrated increases in self-efficacy for HIV disclosure, perceived policy control, and self-efficacy for limiting HIV risk behavior. Immediately post-intervention, MOVE participants reported greater decreases in condomless intercourse with negative/unknown partners. MOVE may have potential to improve the health of Black Y-GBM living with HIV and reduce further transmission.

Malaria Transmission Intensity Likely Modifies RTS, S/AS01 Efficacy Due to a Rebound Effect in Ghana, Malawi, and Gabon

BACKGROUND

RTS,S/AS01 is the first malaria vaccine to be approved and recommended for widespread implementation by the World Health Organization (WHO). Trials reported lower vaccine efficacies in higher-incidence sites, potentially due to a "rebound" in malaria cases in vaccinated children. When naturally acquired protection in the control group rises and vaccine protection in the vaccinated wanes concurrently, malaria incidence can become greater in the vaccinated than in the control group, resulting in negative vaccine efficacies.

METHODS

Using data from the 2009-2014 phase III trial (NCT00866619) in Lilongwe, Malawi; Kintampo, Ghana; and Lambaréné, Gabon, we evaluate this hypothesis by estimating malaria incidence in each vaccine group over time and in varying transmission settings. After estimating transmission intensities using ecological variables, we fit models with 3-way interactions between vaccination, time, and transmission intensity.

RESULTS

Over time, incidence decreased in the control group and increased in the vaccine group. Three-dose efficacy in the lowest-transmission-intensity group (0.25 cases per person-year [CPPY]) decreased from 88.2% to 15.0% over 4.5 years, compared with 81.6% to -27.7% in the highest-transmission-intensity group (3 CPPY).

CONCLUSIONS

These findings suggest that interventions, including the fourth RTS,S dose, that protect vaccinated individuals during the potential rebound period should be implemented for high-transmission settings.

Randomized Controlled Trial of a Remote Coaching mHealth Adherence Intervention in Youth Living with HIV

Youth living with HIV (YLWH) in the US have low rates of viral suppression (VS). In a prospective randomized clinical trial (ATN152) that enrolled 89 YLWH on antiretroviral therapy (ART) with detectable viral load, we evaluated a 12 week triggered escalating real-time adherence (TERA) intervention with remote coaching, electronic dose monitoring (EDM), and outreach for missed/delayed doses compared to standard of care (SOC). Median [Q1, Q3] percent days with EDM opening was higher in TERA (72% (47%, 89%)) versus SOC (41% (21%, 59%); p < 0.001) and incidence of numbers of 7 day gaps between openings were lower (TERA to SOC ratio: 0.40; 95% CI 0.30, 0.53; p < 0.001). There were no differences in VS at week 12 (TERA 35%; 95% CI 21%, 51% versus SOC 36%; 95% CI 22%, 51%; p > 0.99) or later time-points. The intervention improved adherence but not VS in heavily ART-experienced YLWH. Remote coaching more closely tailored to the unique dosing patterns and duration of need for youth struggling to reach VS warrants further investigation.

Early post-vaccination gene signatures correlate with the magnitude and function of vaccine-induced HIV envelope-specific plasma antibodies in infant rhesus macaques

Systems vaccinology approaches are important tools in rational vaccine design. Our goal was to determine whether early innate immune responses to the vaccine prime in infant rhesus macaques, immunized with two different HIV envelope (Env) vaccine regimens, were associated with functional antibody responses in the memory phase.

We compared plasma cytokine levels and molecular signatures of a 3M-052-SE adjuvanted HIV Env protein vaccine (n=10) to a regimen combining the adjuvanted HIV Env protein and MVA-HIV Env (n=10) at days (D) 0, 1, and 3 post the vaccine prime. Whole blood transcriptional profiling applying NanoString technology was employed to identify differentially expressed genes (DEG). Innate immune responses were correlated with vaccine-induced adaptive immune responses at weeks 14, 20, 32, and 34.

The vaccine prime induced a rapid, but transient, increase in inflammatory plasma cytokines and changes in mRNA expression that peaked at D1. In the HIV protein group, we identified 31 DEG with increased mRNA levels, whereas a single, downregulated, DEG was identified in the MVA-Env plus Protein group. Day one signatures were positively correlated with week 14 Env-specific IgG responses, and, at week 34, with Env-specific follicular T helper cells and Env-specific antibody-dependent cytotoxicity function, but negatively correlated with Env-specific CD8+ T cell responses. A protein-protein interaction network confirmed that several of the DEG-encoded proteins have predicted interaction partners that are important for B cell activation.

These results support the idea that vaccine-induced HIV-specific antibody and T cell responses can be optimized through the modulation of the vaccine prime.

Supported by National Institutes of Health grants R01 DE028146 , P01 AI117915 , T32 5108303 , the Office of Research Infrastructure Programs/OD P510D011107 (CNPRC), and the Center for AIDS Research award P30AI050410

Impacts of Initial Prescription Length and Prescribing Limits on Risk of Prolonged Postsurgical Opioid Use

BACKGROUND

In response to concerns about opioid addiction following surgery, many states have implemented laws capping the days supplied for initial postoperative prescriptions. However, few studies have examined changes in the risk of prolonged opioid use associated with the initial amount prescribed.

OBJECTIVE

The objective of this study was to estimate the risk of prolonged opioid use associated with the length of initial opioid prescribed and the potential impact of prescribing limits.

RESEARCH DESIGN

Using Medicare insurance claims (2007-2017), we identified opioid-naive adults undergoing surgery. Using G-computation methods with logistic regression models, we estimated the risk of prolonged opioid use (≥1 opioid prescription dispensed in 3 consecutive 30-d windows following surgery) associated with the varying initial number of days supplied. We then estimate the potential reduction in cases of prolonged opioid use associated with varying prescribing limits.

RESULTS

We identified 1,060,596 opioid-naive surgical patients. Among the 70.0% who received an opioid for postoperative pain, 1.9% had prolonged opioid use. The risk of prolonged use increased from 0.7% (1 d supply) to 4.4% (15+ d). We estimated that a prescribing limit of 4 days would be associated with a risk reduction of 4.84 (3.59, 6.09)/1000 patients and would be associated with 2255 cases of prolonged use potentially avoided. The commonly used day supply limit of 7 would be associated with a smaller reduction in risk [absolute risk difference=2.04 (-0.17, 4.25)/1000].

CONCLUSIONS

The risk of prolonged opioid use following surgery increased monotonically with increasing prescription duration. Common prescribing maximums based on days supplied may impact many patients but are associated with relatively low numbers of reduced cases of prolonged use. Any prescribing limits need to be weighed against the need for adequate pain management.

Different adjuvanted pediatric HIV envelope vaccines induced distinct plasma antibody responses despite similar B cell receptor repertoires in infant rhesus macaques

Different HIV vaccine regimens elicit distinct plasma antibody responses in both human and nonhuman primate models. Previous studies in human and non-human primate infants showed that adjuvants influenced the quality of plasma antibody responses induced by pediatric HIV envelope vaccine regimens. We recently reported that use of the 3M052-SE adjuvant and longer intervals between vaccinations are associated with higher magnitude of antibody responses in infant rhesus macaques. However, the impact of different adjuvants in HIV vaccine regimens on the developing infant B cell receptor (BCR) repertoire has not been studied. This study evaluated whether pediatric HIV envelope vaccine regimens with different adjuvants induced distinct antigen-specific memory B cell repertoires and whether specific immunoglobulin (Ig) immunogenetic characteristics are associated with higher magnitude of plasma antibody responses in vaccinated infant rhesus macaques. We utilized archived preclinical pediatric HIV vaccine studies PBMCs and tissue samples from 19 infant rhesus macaques immunized either with (i) HIV Env protein with a squalene adjuvant, (ii) MVA-HIV and Env protein co-administered using a 3-week interval, (iii) MVA-HIV prime/ protein boost with an extended 6-week interval between immunizations, or (iv) with HIV Env administered with 3M-052-SE adjuvant. Frequencies of vaccine-elicited HIV Env-specific memory B cells from PBMCs and tissues were similar across vaccination groups (frequency range of 0.06–1.72%). There was no association between vaccine-elicited antigen-specific memory B cell frequencies and plasma antibody titer or avidity. Moreover, the epitope specificity and Ig immunogenetic features of vaccine-elicited monoclonal antibodies did not differ between the different vaccine regimens. These data suggest that pediatric HIV envelope vaccine candidates with different adjuvants that previously induced higher magnitude and quality of plasma antibody responses in infant rhesus macaques were not driven by distinct antigen-specific memory BCR repertoires.

Day-of-Surgery Gabapentinoids and Prolonged Opioid Use: A Retrospective Cohort Study of Medicare Patients Using Electronic Health Records

BACKGROUND

While preoperative gabapentinoids are commonly used in surgical multimodal analgesia protocols, little is known regarding the effects this therapy has on prolonged postsurgical opioid use. In this observational study, we used data from a large integrated health care system to estimate the association between preoperative day-of-surgery gabapentinoids and the risk of prolonged postsurgical opioid use.

METHODS

We identified adults age ≥65 years undergoing major therapeutic surgical procedures from a large integrated health care system from 2016 to 2019. Exposure to preoperative gabapentinoids on the day of surgery was measured using inpatient medication administration records, and the outcome of prolonged opioid use was measured using outpatient medication orders. We used stabilized inverse probability of treatment-weighted log-binomial regression to estimate risk ratios and 95% confidence intervals (CIs) of prolonged opioid use, comparing patients who received preoperative gabapentinoids to those who did not and adjusting for relevant clinical factors. The main analysis was conducted in the overall surgical population, and a secondary analysis was conducted among procedures where at least 30% of all patients received a preoperative gabapentinoid.

RESULTS

Overall, 13,958 surgical patients met inclusion criteria, of whom 21.0% received preoperative gabapentinoids. The observed 90-day risk of prolonged opioid use following surgery was 0.91% (95% CI, 0.77-1.08). Preoperative gabapentinoid administration was not associated with a reduced risk of prolonged opioid use in the main analysis conducted in a broad surgical population (adjusted risk ratio [adjRR], 1.19 [95% CI, 0.67-2.12]) or in the secondary analysis conducted in patients undergoing colorectal resection, hip arthroplasty, knee arthroplasty, or hysterectomy (adjRR, 1.01 [95% CI, 0.30-3.33]).

CONCLUSIONS

In a large integrated health system, we did not find evidence that preoperative gabapentinoids were associated with reduced risk of prolonged opioid use in patients undergoing a broad range of surgeries.

CD8 co-receptor links T cell avidity and metabolism

This study investigated the mechanistic basis behind the reported superior efficacy of high-avidity CD8 T cells. CMV and HIV are both chronic viral infections, but while CMV-specific CD8 T cells can mediate lifelong viral control, in untreated HIV infection HIV-specific CD8 T cells progressively lose function. Using in vitro studies of human cells, we show that avidity-dependent downregulation of the CD8 co-receptor directly programs metabolism, due to a novel association between CD8 and the glucose transporter GLUT1. We used flow cytometry to profile ex vivo and virus-specific CD8 T cells from HIV-infected individuals on antiretroviral therapy. Ex vivo, cells expressing low levels of CD8 (CD8dim) expressed more CD69 but less cell surface GLUT1, and took up less glucose (2-NBDG) than CD8bright T cells. Following antigen stimulation, CD3, CD8, and GLUT1 were downregulated from the cell surface in an avidity-dependent manner. CMV-specific CD8 T cells, which were of higher avidity, downregulated these proteins to a greater extent than lower-avidity HIV-specific CD8 T cells. GLUT1 downregulation strongly correlated with CD8 but not CD3 downregulation. Antibody-mediated downregulation of CD8 from the cell surface resulted in reduced glucose uptake and increased fatty acid (Bodipy) uptake, independent of CD3. Finally, CD3, CD8, and GLUT1 downregulation by HIV-specific CD8 T cells was impaired following viral escape mutations that reduced CD8 T cell avidity. We confirmed this finding in a transduction setting with a single clonal TCR. Our data reveal a novel function of the CD8 co-receptor, linking the avidity and metabolism of CD8 T cells.

Correlates of High HIV Viral Load and Antiretroviral Therapy Adherence Among Viremic Youth in the United States Enrolled in an Adherence Improvement Intervention

A sizable portion of youth (ages 13-24) living with HIV in the United States have unsuppressed viral load. The AIDS Interventions (ATN) 152 study [evaluating the Triggered Escalating Real-Time Adherence (TERA) intervention] baseline data were examined to identify correlates of high viremia (>5000 copies/mL) and self-reported adherence, which can help in planning of differentiated services for viremic youth. Depression, HIV-stigma, and cannabis use were common in this sample of 87 youth. Almost half (48%) had high viremia, which associated with enacted stigma, moderate- to high-risk alcohol use, mental health diagnosis, and age ≥21. Self-reported adherence was related to viral load and associated with mental and physical health functioning, depression, social support, self-confident decision-making, total and internalized stigma, adherence motivation, and report of a missed a care visit in the past 6 months. Mental health emerged as a common correlate of viral load and adherence. Clinical Trial Registration number: NCT03292432.

Neurodevelopmental Outcomes of Children Following In Utero Exposure to Zika in Nicaragua

Background

Neurodevelopmental outcomes of asymptomatic children exposed to Zika virus (ZIKV) in utero are not well characterized.

Methods

We prospectively followed 129 newborns without evidence of congenital Zika syndrome (CZS) up to 24 months of age. Participants were classified as ZIKV exposed or ZIKV unexposed. The Mullen Scales of Early Learning (MSEL) was administered in the participants’ homes at 6, 12, 15, 18, 21, and 24 months of age by trained psychologists. Sociodemographic data, medical history, and infant anthropometry at birth were collected at each home visit. Our primary outcome was the Mullen Early Learning Composite Score (ECL) at 24 months of age between our 2 exposure groups. Secondary outcomes were differences in MSEL subscales over time and at 24 months.

Results

Of 129 infants in whom exposure status could be ascertained, 32 (24.8%) met criteria for in utero ZIKV exposure and 97 (75.2%) did not. There were no differences in maternal age, maternal educational attainment, birthweight, or gestational age at birth between the 2 exposure groups. The adjusted means and standard errors (SEs) for the ELC score between the ZIKV-exposed children compared to ZIKV-unexposed children were 91.4 (SE, 3.1) vs 96.8 (SE, 2.4) at 12 months and 93.3 (SE, 2.9) vs 95.9 (SE, 2.3) at 24 months. In a longitudinal mixed model, infants born to mothers with an incident ZIKV infection (P = .01) and low-birthweight infants (<2500 g) (P = .006) had lower composite ECL scores.

Conclusions

In this prospective cohort of children without CZS, children with in utero ZIKV exposure had lower neurocognitive scores at 24 months.

AVERAGE TREATMENT EFFECTS IN THE PRESENCE OF UNKNOWN INTERFERENCE

We investigate large-sample properties of treatment effect estimators under unknown interference in randomized experiments. The inferential target is a generalization of the average treatment effect estimand that marginalizes over potential spillover effects. We show that estimators commonly used to estimate treatment effects under no interference are consistent for the generalized estimand for several common experimental designs under limited but otherwise arbitrary and unknown interference. The rates of convergence depend on the rate at which the amount of interference grows and the degree to which it aligns with dependencies in treatment assignment. Importantly for practitioners, the results imply that if one erroneously assumes that units do not interfere in a setting with limited, or even moderate, interference, standard estimators are nevertheless likely to be close to an average treatment effect if the sample is sufficiently large. Conventional confidence statements may, however, not be accurate.

Maternal HIV, antiretroviral timing, and spontaneous preterm birth in an urban Zambian cohort: the role of local and systemic inflammation

OBJECTIVE

To assess plasma and vaginal inflammation in three antenatal groups (HIV-uninfected women, HIV-infected women entering care on preconceptional ART, and HIV-infected women not on preconceptional ART) and whether these measures are associated with spontaneous preterm birth (sPTB).

DESIGN

Case--control study nested within a pregnancy cohort in Lusaka, Zambia.

METHODS

We analyzed 11 pro-inflammatory and two anti-inflammatory markers in 207 women with paired plasma and vaginal specimens collected between 16 and 20 gestational weeks. Among 51 HIV-infected women, we repeated the assays in 24-34-week samples. We used confirmatory factor analysis to create inflammation scores and compared them among the three groups.

RESULTS

At baseline, HIV-infected women not on ART had higher vaginal pro-inflammatory scores than HIV-uninfected women [mean 0.37 (95% CI -0.06 to 0.80) vs. -0.02 (-0.32 to 0.27), P = 0.02]. In repeat testing, women not on preconceptional ART had an increase in vaginal inflammation between the baseline and 24-34-week visits compared with those continuing preconceptional ART [mean 0.62 (95% CI -0.80 to 4.20) vs. -0.07 (-2.78 to 2.11), P = 0.04]. In multivariate analyses, baseline vaginal inflammation predicted sPTB (aOR 1.5; 95% CI 1.0-2.3; P = 0.02). Plasma inflammation did not differ by HIV or ART exposure and was not associated with sPTB.

CONCLUSION

Women not receiving ART at entry into pregnancy care had more vaginal inflammation than women entering on treatment. They also experienced an increase in vaginal inflammation between the two sampling timepoints, possibly as a consequence of ART initiation. Vaginal (but not systemic) inflammation was associated with sPTB and offers a potential mechanistic insight into this important adverse birth outcome.

Design and analysis considerations for a sequentially randomized HIV prevention trial

TechStep is a randomized trial of a mobile health interventions targeted towards transgender adolescents. The interventions include a short message system, a mobile-optimized web application, and electronic counseling. The primary outcomes are self-reported sexual risk behaviors and uptake of HIV preventing medication. In order that we may evaluate the efficacy of several different combinations of interventions, the trial has a sequentially randomized design. We use a causal framework to formalize the estimands of the primary and key secondary analyses of the TechStep trial data. Targeted minimum loss-based estimators of these quantities are described and studied in simulation.

SARS-CoV-2 Seroprevalence among a Southern U.S. Population Indicates Limited Asymptomatic Spread under Physical Distancing Measures

Characterizing the asymptomatic spread of SARS-CoV-2 is important for understanding the COVID-19 pandemic. This study was aimed at determining asymptomatic spread of SARS-CoV-2 in a suburban, Southern U.S. population during a period of state restrictions and physical distancing mandates. This is one of the first published seroprevalence studies from North Carolina and included multicenter, primary care, and emergency care facilities serving a low-density, suburban and rural population since description of the North Carolina state index case introducing the SARS-CoV-2 respiratory pathogen to this population. To estimate point seroprevalence of SARS-CoV-2 among asymptomatic individuals over time, two cohort studies were examined. The first cohort study, named ScreenNC, was comprised of outpatient clinics, and the second cohort study, named ScreenNC2, was comprised of inpatients unrelated to COVID-19. Asymptomatic infection by SARS-CoV-2 (with no clinical symptoms) was examined using an Emergency Use Authorization (EUA)-approved antibody test (Abbott) for the presence of SARS-CoV-2 IgG. This assay as performed under CLIA had a reported specificity/sensitivity of 100%/99.6%. ScreenNC identified 24 out of 2,973 (0.8%) positive individuals among asymptomatic participants accessing health care during 28 April to 19 June 2020, which was increasing over time. A separate cohort, ScreenNC2, sampled from 3 March to 4 June 2020, identified 10 out of 1,449 (0.7%) positive participants.IMPORTANCE This study suggests limited but accelerating asymptomatic spread of SARS-CoV-2. Asymptomatic infections, like symptomatic infections, disproportionately affected vulnerable communities in this population, and seroprevalence was higher in African American participants than in White participants. The low, overall prevalence may reflect the success of shelter-in-place mandates at the time this study was performed and of maintaining effective physical distancing practices among suburban populations. Under these public health measures and aggressive case finding, outbreak clusters did not spread into the general population.

CD3 and CD8 coreceptor down-modulation are inversely associated with CD8 T cell functional avidity in humans

This study investigated the function of memory CD8 T cells in HIV-infected people durably suppressed on antiretroviral therapy (HIV+ cART). We assessed bulk and virus-specific memory CD8 T cells in HIV+ cART and HIV-seronegative individuals (HIV−) by flow cytometry. We observed a population of CD3+ CD8dim CD14− CD16− (CD8dim) T cells that was expanded as a percentage of total CD8 T cells in both HIV− and CMV-seropositive individuals. Bulk memory CD8dim T cells expressed significantly higher CD69 and less MHC Class I and CD127 ex vivo than CD8bright T cells, suggesting recent activation. CD8dim T cells expressed less GLUT1 and PGC-1α and took up less glucose (2-NBDG) and lipid (Bodipy) than CD8bright T cells, indicating relatively lower metabolic activity. Multimer reactivity was used to examine CMV-, EBV- and HIV-specific CD8 T cells ex vivo. Virus-specific populations were consistently CD8high. However, after peptide stimulation, antigen-specific CD8 T cells down-regulated CD3 and CD8. CMV-specific CD8 T cells down-regulated CD3 and CD8 more than HIV-specific cells. CD3 and CD8 downregulation were strongly correlated with the functional avidity of the response. A strong correlation between GLUT1 down-regulation and CD8 down-regulation was also observed, suggesting an association between CD8 expression and metabolic activity. These results suggest that the expanded CD8dim population in HIV+ cART individuals, who are &gt;90% CMV-seropositive, may be driven by ongoing activation of high-avidity CMV-specific CD8 T cells. They also suggest that different virus-specific CD8 T cell populations differentially downregulate components of the TCR complex and metabolism after antigen stimulation, possibly to avoid excessive activation.

Neonatal vaccination primes persistent HIV Env-specific antibodies that are augmented by a single booster immunization in late infancy

Breastmilk transmission of HIV remains unacceptably high. Vaccine approaches that prime robust virus-specific immune responses in infancy may prevent acquisition during the breastfeeding period. Moreover, vaccine responses that generate robust immunological memory that persists into adolescence could prevent sexual transmission later in life.

The current study investigated the immunological benefit of late boosting following vaccination in infancy. Two groups of neonatal rhesus macaques were immunized with a clade C HIV Env protein adjuvanted with 3M-052 stable emulsion (SE) vaccine (Env Only) alone or together with a modified vaccinia Ankara (MVA) vector expressing HIV Env and SIV Gag (MVA/Env) at 0, 6, and 12 weeks of age. Env-specific B cells were present in blood yet absent from lymph nodes in the Env Only group by week 14. At week 32, 18 weeks following the last immunization, we could still detect Env-specific plasma IgG responses capable of autologous and heterologous HIV Env binding, Env-specific ADCC activity and CD4 blocking in both groups. A final booster immunization at week 32 enhanced avidity and function of Env-specific plasma IgG in both groups. These data confirmed previous work by our group that demonstrated HIV Env protein adjuvanted with the TLR7/8-based 3M-052-SE primed greater immune responses than Span85-Tween 80 Squalene.

Our data from the Env Only vaccine regimen are consistent with the induction of Env-specific antibody responses in human infants. These results support the idea that early life vaccination is an effective means to induce persistent HIV Env-specific IgG responses that can be boosted in infancy and could be exploited to drive protective immunity against HIV acquisition prior to sexual debut.

Case reduction and cost-effectiveness of the RTS,S/AS01 malaria vaccine alongside bed nets in Lilongwe, Malawi

BACKGROUND

RTS,S/AS01, the most advanced vaccine against malaria, is now undergoing pilot implementation in Malawi, Ghana, and Kenya where an estimated 360,000 children will be vaccinated each year. In this study we evaluate RTS,S/AS01 alongside bed net use and estimate cost-effectiveness.

METHODS

RTS,S/AS01 phase III trial and bed net prevalence data were used to determine the effect of vaccination in the urban/periurban and rural areas of Lilongwe, Malawi. Cost data were used to calculate the cost-effectiveness of various interventions over three years.

FINDINGS

Since bed nets reduce malaria incidence and homogeneous vaccine efficacy was assumed, participants without bed nets received greater relative benefit from vaccination with RTS,S/AS01 than participants with bed nets. Similarly, since malaria incidence in rural Lilongwe is higher than in urban Lilongwe, the impact and cost-effectiveness of vaccine interventions is increased in rural areas. In rural Lilongwe, we estimated that vaccinating one child without a bed net would prevent 2·59 (1·62 to 3·38) cases of malaria over three years, corresponding to a cost of $10·08 (7·71 to 16·13) per case averted. Alternatively, vaccinating one child with a bed net would prevent 1·59 (0·87 to 2·57) cases, corresponding to $16·43 (10·16 to 30·06) per case averted. Providing RTS,S/AS01 to 30,000 children in rural Lilongwe was estimated to cost $782,400 and to prevent 58,611 (35,778 to 82,932) cases of malaria over a three-year period. Joint interventions providing both vaccination and bed nets (to those without them) were estimated to prevent additional cases of malaria and to be similarly cost-effective, compared to vaccine-only interventions.

INTERPRETATION

To maximize malaria prevention, vaccination and bed net distribution programs could be integrated.

FUNDING

Impacts of Environment, Host Genetics and Antigen Diversity on Malaria Vaccine Efficacy (1R01AI137410-01).

HIV-Specific T Cell Responses Are Highly Stable on Antiretroviral Therapy

HIV infection induces a robust T cell response that is sustained by high viremia, but falls following the onset of antiretroviral therapy (ART). Relatively little has been reported on the subsequent stability of the HIV-specific T cell response in individuals on durable therapy. Such data are critical for powering clinical trials testing T cell-based immunotherapies. In a cross-sectional study, HIV-specific T cell responses were detectable by ex vivo interferon (IFN)-γ ELISpot (average ∼1,100 spot-forming units [SFUs]/106 peripheral blood mononuclear cells) in persons living with HIV (PLWH; n = 34), despite median durable ART suppression of 5.0 years. No substantial association was detected between the summed HIV-specific T cell response and the size of the replication-competent HIV reservoir. T cell responses were next measured in participants sampled weekly, monthly, or yearly. HIV-specific T cell responses were highly stable over the time periods examined; within-individual variation ranged from 16% coefficient of variation (CV) for weekly to 27% CV for yearly sampling. These data were used to generate power calculations for future immunotherapy studies. The stability of the HIV-specific T cell response in suppressed PLWH will enable powered studies of small sizes (e.g., n = 6-12), facilitating rapid and iterative testing for T cell-based immunotherapies against HIV.

Simian-Human Immunodeficiency Virus SHIV.CH505-Infected Infant and Adult Rhesus Macaques Exhibit Similar Env-Specific Antibody Kinetics, despite Distinct T-Follicular Helper and Germinal Center B Cell Landscapes

Global elimination of pediatric human immunodeficiency virus (HIV) infections will require the development of novel immune-based approaches, and understanding infant immunity to HIV is critical to guide the rational design of these intervention strategies. Despite their immunological immaturity, chronically HIV-infected children develop broadly neutralizing antibodies (bnAbs) more frequently and earlier than adults do. However, the ontogeny of humoral responses during acute HIV infection is poorly defined in infants and challenging to study in human cohorts due to the presence of maternal antibodies. To further our understanding of age-related differences in the development of HIV-specific immunity during acute infection, we evaluated the generation of virus-specific humoral immune responses in infant (n = 6) and adult (n = 12) rhesus macaques (RMs) infected with a transmitted/founder (T/F) simian-human immunodeficiency virus (SHIV) (SHIV.C.CH505 [CH505]). The plasma HIV envelope-specific IgG antibody kinetics were similar in SHIV-infected infant and adult RMs, with no significant differences in the magnitude or breadth of these responses. Interestingly, autologous tier 2 virus neutralization responses also developed with similar frequencies and kinetics in infant and adult RMs, despite infants exhibiting significantly higher follicular T helper cell (Tfh) and germinal center B cell frequencies than adults. Finally, we show that plasma viral load was the strongest predictor of the development of autologous virus neutralization in both age groups. Our results indicate that the humoral immune response to SHIV infection develops with similar kinetics among infant and adult RMs, suggesting that the early-life immune system is equipped to respond to HIV-1 and promote the production of neutralizing HIV antibodies.IMPORTANCE There is a lack of understanding of how the maturation of the infant immune system influences immunity to HIV infection or how these responses differ from those of adults. Improving our knowledge of infant HIV immunity will help guide antiviral intervention strategies that take advantage of the unique infant immune environment to successfully elicit protective immune responses. We utilized a rhesus macaque model of SHIV infection as a tool to distinguish the differences in HIV humoral immunity in infants versus adults. Here, we demonstrate that the kinetics and quality of the infant humoral immune response to HIV are highly comparable to those of adults during the early phase of infection, despite distinct differences in their Tfh responses, indicating that slightly different mechanisms may drive infant and adult humoral immunity.

Triggered Escalating Real-Time Adherence Intervention to Promote Rapid HIV Viral Suppression Among Youth Living With HIV Failing Antiretroviral Therapy: Protocol for a Triggered Escalating Real-Time Adherence Intervention

Background

Youth living with HIV (YLWH) are confronted with many self-care challenges that can be experienced as overwhelming in the context of normal developmental processes that characterize adolescence and young adulthood. A sizable minority of YLWH have unsuppressed viral loads in the United States attributable to antiretroviral therapy (ART) nonadherence. Interventions to promote sustained viral suppression in YLWH are needed.

Objective

The aim of this study is to evaluate the efficacy of the Triggered Escalating Real-Time Adherence (TERA) intervention in comparison with standard of care (SOC) in YLWH (aged 13-24 years) failing ART on (1) primary outcome measures—HIV viral suppression (VLS), defined as both <200 copies/ml and <50 copies/ml at 12 weeks, and (2) secondary outcome measures—VLS rates and rates of ART adherence at 24, 36, and 48 weeks as well as patterns of adherence over time as measured by an electronic dose monitoring (EDM) device.

Methods

The TERA study is a phase 2, multisite clinical trial conducted with 120 YLWH failing ART (randomized 1:1 to TERA or SOC) at participating clinical sites within the Adolescent Medicine Trials Network for HIV/AIDS Interventions (ATN). Participants are followed for a total of 48 weeks. For TERA arm participants, the first 12 weeks involve delivery of the intervention. For all participants, clinical outcomes are collected throughout follow-up, and adherence is assessed using EDM over the full 48 weeks. During the 12-week intervention period, TERA arm participants receive 3 remote coaching sessions delivered in clinic via videoconferencing timed to coincide with baseline and follow-up clinical visits, text message reminders when the EDM has not been opened at dose time (which escalate to 2-way theory-informed short message service coaching interactions in response to real-time nonadherence), and review of dosing graphs produced by EDM at follow-up visits.

Results

Launch dates for enrollment varied by site. Enrollment began in April 2018 and is expected to be completed by August 2019, with results presented by the second quarter of 2021.

Conclusions

Effective, generalizable, and scalable approaches to rapidly assist YLWH failing to achieve and sustain VLS may have a substantial impact on individual health and efforts to curb transmission. Coaching for a brief but intensive period from remote coaches and using communication channels common to youth may offer multiple unique advantages in promoting self-care.

Trial Registration

ClinicalTrials.gov NCT03292432; https://clinicaltrials.gov/ct2/show/NCT03292432 (Archived by WebCite at http://www.webcitation.org/768J8ijjp).

International Registered Report Identifier (IRRID)

DERR1-10.2196/11416

Reimagining Health Communication: A Noninferiority Randomized Controlled Trial of Crowdsourced Intervention in China

BACKGROUND

Crowdsourcing, the process of shifting individual tasks to a large group, may be useful for health communication, making it more people-centered. We aimed to evaluate whether a crowdsourced video is noninferior to a social marketing video in promoting condom use.

METHODS

Men who have sex with men (≥16 years old, had condomless sex within 3 months) were recruited and randomly assigned to watch 1 of the 2 videos in 2015. The crowdsourced video was developed through an open contest, and the social marketing video was designed by using social marketing principles. Participants completed a baseline survey and follow-up surveys at 3 weeks and 3 months postintervention. The outcome was compared with a noninferiority margin of +10%.

RESULTS

Among the 1173 participants, 907 (77%) and 791 (67%) completed the 3-week and 3-month follow-ups. At 3 weeks, condomless sex was reported by 146 (33.6%) of 434 participants and 153 (32.3%) 473 participants in the crowdsourced and social marketing arms, respectively. The crowdsourced intervention achieved noninferiority (estimated difference, +1.3%; 95% confidence interval, -4.8% to 7.4%). At 3 months, 196 (52.1%) of 376 individuals and 206 (49.6%) of 415 individuals reported condomless sex in the crowdsourced and social-marketing arms (estimated difference: +2.5%, 95% confidence interval, -4.5 to 9.5%). The 2 arms also had similar human immunodeficiency virus testing rates and other condom-related secondary outcomes.

CONCLUSIONS

Our study demonstrates that crowdsourced message is noninferior to a social marketing intervention in promoting condom use among Chinese men who have sex with men. Crowdsourcing contests could have a wider reach than other approaches and create more people-centered intervention tools for human immunodeficiency virus control.

Adolescent Medicine Trials Network for HIV/AIDS Interventions Data Harmonization: Rationale and Development of Guidelines

Background

The Adolescent Medicine Trials Network for HIV/AIDS Interventions (ATN) research program aims to defeat the rising HIV epidemic among adolescents and young adults in the United States.

Objective

This study aims to optimize cross-study analyses and comparisons of standardized measures (variables) collected in the ATN.

Methods

Guidelines were developed for harmonizing measures to be collected across ATN studies.

Results

Eight domains were identified for harmonization—Demographics and Socioeconomic Characteristics, Sexual Behavior and Risk, Substance Use and Abuse, HIV-Positive Cascade, HIV-Negative Cascade, Mental Health, Social Support and Isolation, and Pre-exposure Prophylaxis Cascade.

Conclusions

The collection of selected key measures in a uniform manner across studies facilitates the characterization of participant populations, comparisons between studies, and pooled analysis of data from multiple studies.

A Reproducible, Objective Method Using MitoTracker® Fluorescent Dyes to Assess Mitochondrial Mass in T Cells by Flow Cytometry

MitoTracker ® dyes are fluorescent compounds that allow cellular mitochondrial content to be measured semi‐quantitatively by flow cytometry and have been used extensively in immunology publications. However, the parameters commonly reported, mean or median fluorescence intensity and percentage of cells that are MitoTracker® “high”, can be influenced by variability in cytometer setup, dye stability, and operator subjectivity, making it difficult to compare data between experiments. Here, we describe a method to identify MitoTracker® “high” populations in an objective manner. When analyzing data, we first removed outliers using a pre‐specified threshold, determined the fluorescence intensity of the brightest and dimmest events to obtain the fluorescence range and then gated cells within the top 90% of this range. This strategy substantially reduced variability between technical replicates and produced consistent results when data were analyzed by different operators. Consistent with previous reports and other analysis strategies, this analysis method demonstrated that within an individual, CD4⁺ T cells exhibit significantly higher mitochondrial mass than CD8⁺ T cells. Objective gating increases the reliability and utility of data generated using MitoTracker® dyes. © 2018 The Authors. Cytometry Part A published by Wiley Periodicals, Inc. on behalf of International Society for Advancement of Cytometry.

γδ T cells: an immunotherapeutic approach for HIV cure strategies

Current strategies aimed to cure HIV infection are based on combined efforts to reactivate the virus from latency and improve immune effector cell function to clear infected cells. These strategies are primarily focused on CD8+ T cells and approaches are challenging due to insufficient HIV antigen production from infected cells and poor HIV-specific CD8+ T cells. γδ T cells represent a unique subset of effector T cells that can traffic to tissues, and selectively target cancer or virally infected cells without requiring MHC presentation. We analyzed whether γδ T cells represent a complementary/alternative immunotherapeutic approach towards HIV cure strategies. γδ T cells from HIV-infected virologically suppressed donors were expanded with bisphosphonate pamidronate (PAM) and cells were used in autologous cellular systems ex vivo. These cells (a) are potent cytotoxic effectors able to efficiently inhibit HIV replication ex vivo, (b) degranulate in the presence of autologous infected CD4+ T cells, and (c) specifically clear latently infected cells after latency reversal with vorinostat. This is the first proof of concept to our knowledge showing that γδ T cells target and clear autologous HIV reservoirs upon latency reversal. Our results open potentially new insights into the immunotherapeutic use of γδ T cells for current interventions in HIV eradication strategies.

Stable Caloric Intake and Continued Virologic Suppression for HIV-Positive Antiretroviral Treatment-Experienced Women After Switching to a Single-Tablet Regimen of Emtricitabine, Rilpivirine, and Tenofovir Disoproxil Fumarate

Benefits of switching to a single-tablet regimen (STR) of emtricitabine/rilpivirine/tenofovir (FTC/RPV/TDF) in virologically suppressed antiretroviral treatment (ART) experienced HIV-positive women include pregnancy category B rating and lack of clinically significant drug interactions between RPV and oral contraceptives. Unfortunately, studies involving switching to FTC/RPV/TDF enrolled fewer than 25% women. We undertook this 48-week study to assess the ability of virologically suppressed HIV-positive women switching to RPV STR to remain virologically suppressed and comply with the caloric intake requirement. HIV-positive women on ART with viral load <50 c/mL for 6 months before study entry and no known resistance to FTC, TDF, or RPV were enrolled and switched to STR RPV/FTC/TDF. Caloric intake (≥400 kcal) compliance and concurrency with oral STR RPV/FTC/TDF were evaluated with a 3-day food diary, which was validated by obtaining participant's caloric consumption through phone calls on randomly chosen dates. For each 3-day food diary, the daily median caloric intake and median value for each macronutrient consumed concurrent with FTC/RPV/TDF were computed. Medication adherence was measured using a visual analog scale. We enrolled 33 women, 73% of whom were African American. At week 48, virologic suppression (HIV RNA <40 c/mL) was maintained in 96% of women, including those (n = 4) who reported imperfect ART adherence. The daily median caloric intake concurrent with FTC/RPV/TDF was 820 kcal by food diary and 677 kcal by random phone call. Median kcal intake (food diary) did not change significantly from baseline (684 kcal) to week 48 (820 kcal); median change 102 kcal, p = .15. Women who reported noncompliance with a ≥400 kcal meal did not experience virologic failure. Significant concordance between caloric adherence and virologic suppression was not detected. Our study demonstrated that HIV-positive women who switched to STR FTC/RPV/TDF continued to experience virologic suppression and were readily able to comply with the recommended caloric intake requirement.

Timing of HIV Seroreversion Among HIV-Exposed, Breastfed Infants in Malawi: Type of HIV Rapid Test Matters

Introduction Rapid HIV serological tests are a cost-effective, point-of-care test among HIV exposed infants but cannot distinguish between maternal and infant antibodies. The lack of data on the timing of decay of maternal antibodies in young infants hinders the potential use of rapid tests in exposed infants. We aimed to determine the time to seroreversion for two commonly used rapid tests in a prospective cohort of HIV-exposed breastfeeding infants ages 3–18 months of life. Methods We collected data on the performance of two commonly used rapid tests (Determine and Unigold) in Malawi between 2008 and 2012 or at the University of North Carolina between 2014 and 2015. Time to seroreversion was estimated for both rapid tests using the Kaplan–Meier product limit estimator which allows for interval censored data. Results At 3 months of age, 3 % of infants had seroreverted according to Determine and 7 % had seroreverted according to Unigold. About one in four infants had achieved seroreversion by 4 months using Unigold, but only about one in twelve infants by 4 months when using Determine. More than 95 % of all infants had seroverted by 7 months according to Unigold and by 12 months according to the Determine assay. Discussion We show that the time of seroreversion depends greatly on the type of test used. Our results highlight the need for recommendations to specify the timing and type of test used in the context of infant HIV detection in resource-poor settings, and base the interpretation of test result on knowledge of time to seroreversion of the selected test.

Comparing the effectiveness of a crowdsourced video and a social marketing video in promoting condom use among Chinese men who have sex with men: a study protocol

INTRODUCTION

Crowdsourcing has been used to spur innovation and increase community engagement in public health programmes. Crowdsourcing is the process of giving individual tasks to a large group, often involving open contests and enabled through multisectoral partnerships. Here we describe one crowdsourced video intervention in which a video promoting condom use is produced through an open contest. The aim of this study is to determine whether a crowdsourced intervention is as effective as a social marketing intervention in promoting condom use among high-risk men who have sex with men (MSM) and transgender male-to-female (TG) in China.

METHOD

We evaluate videos developed by crowdsourcing and social marketing. The crowdsourcing contest involved an open call for videos. Entries were judged on capacity to promote condom use, to be shareable or 'go viral' and to give value to the individual. 1170 participants will be recruited for the randomised controlled trial. Participants need to be MSM age 16 and over who have had condomless anal sex in the last 3 months. Recruitment will be through an online banner ad on a popular MSM web page and other social media platforms. After completing an initial survey, participants will be randomly assigned to view either the social marketing video or the crowdsourcing video. Follow-up surveys will be completed at 3 weeks and 3 months after initial intervention to evaluate condomless sex and related secondary outcomes. Secondary outcomes include condom social norms, condom negotiation, condom self-efficacy, HIV/syphilis testing, frequency of sex acts and incremental cost.

ETHICS AND DISSEMINATION

Approval was obtained from the ethical review boards of the Guangdong Provincial Center for Skin Diseases and STI Control, UNC and UCSF. The results of this trial will be made available through publication in peer-reviewed journals.

TRIAL REGISTRATION NUMBER

NCT02516930.

Crowdsourcing HIV Test Promotion Videos: A Noninferiority Randomized Controlled Trial in China

BACKGROUND

Crowdsourcing, the process of shifting individual tasks to a large group, may enhance human immunodeficiency virus (HIV) testing interventions. We conducted a noninferiority, randomized controlled trial to compare first-time HIV testing rates among men who have sex with men (MSM) and transgender individuals who received a crowdsourced or a health marketing HIV test promotion video.

METHODS

Seven hundred twenty-one MSM and transgender participants (≥16 years old, never before tested for HIV) were recruited through 3 Chinese MSM Web portals and randomly assigned to 1 of 2 videos. The crowdsourced video was developed using an open contest and formal transparent judging while the evidence-based health marketing video was designed by experts. Study objectives were to measure HIV test uptake within 3 weeks of watching either HIV test promotion video and cost per new HIV test and diagnosis.

RESULTS

Overall, 624 of 721 (87%) participants from 31 provinces in 217 Chinese cities completed the study. HIV test uptake was similar between the crowdsourced arm (37% [114/307]) and the health marketing arm (35% [111/317]). The estimated difference between the interventions was 2.1% (95% confidence interval, -5.4% to 9.7%). Among those tested, 31% (69/225) reported a new HIV diagnosis. The crowdsourced intervention cost substantially less than the health marketing intervention per first-time HIV test (US$131 vs US$238 per person) and per new HIV diagnosis (US$415 vs US$799 per person).

CONCLUSIONS

Our nationwide study demonstrates that crowdsourcing may be an effective tool for improving HIV testing messaging campaigns and could increase community engagement in health campaigns.

CLINICAL TRIALS REGISTRATION

NCT02248558.

The antibody response to influenza vaccination is not impaired in type 2 diabetics

BACKGROUND

Diabetics are considered to be at high risk for complications from influenza infection and type 2 diabetes is a significant comorbidity of obesity. Obesity is an independent risk factor for complications from infection with influenza. Annual vaccination is considered the best strategy for protecting against influenza infection and it's complications. Our previous study reported intact antibody responses 30 days post vaccination in an obese population. This study was designed to determine the antibody response to influenza vaccination in type 2 diabetics.

METHODS

Subjects enrolled were 18 or older without immunosuppressive diseases or taking immunosuppressive medications. A pre-vaccination blood draw was taken at time of enrollment, the subjects received the influenza vaccine and returned 28-32 days later for a post-vaccination blood draw. Height and weight were also obtained at the first visit and BMI was calculated. Antibody levels to the vaccine were determined by both ELISA and hemagglutination inhibition (HAI) assays.

RESULTS

As reported in our previous work, obesity positively correlates with the influenza antibody response (p=0.02), while age was negatively correlated with antibody response (p<0.001). In both year 1 and year 2 of our study there was no significant difference in the percentage of the type 2 diabetic subjects classified as seroprotected or a responder to the influenza vaccine compared to the non-diabetic subjects.

CONCLUSIONS

These data are important because they demonstrate that diabetics, considered a high risk group during influenza season, are able to mount an antibody response to influenza vaccination that may protect them from influenza infection.

Effects of cotrimoxazole prophylactic treatment on adverse health outcomes among HIV-exposed, uninfected infants

BACKGROUND

The World Health Organization guidelines recommend cotrimoxazole prophylactic treatment (CPT) for all HIV-exposed infants from age 6 weeks to the cessation of breastfeeding and the exclusion of HIV infection. There are limited data on the effects of CPT among this population of infants. We examined the effects of CPT on adverse health outcomes among HIV-exposed infants during the first 36 weeks of life using data from the Breastfeeding, Antiretrovirals and Nutrition study, a large clinical trial of antiretroviral drugs given to the mother or infant for the prevention of HIV transmission during breastfeeding.

METHODS

For the analysis, we assigned a status of CPT-exposed to infants who were participating in the study after the CPT program started. We estimated unadjusted and adjusted hazard ratios for the effect of CPT status on time to incident malaria, severe illness or death, anemia, and weight-for-age Z score < -2.0. Participation in the study was limited to focus exclusively on HIV-exposed, uninfected infants.

RESULTS

The hazard ratio for the effect of CPT on incident malaria was 0.35 (95% confidence interval: 0.21, 0.57) during the first 10 weeks of CPT exposure and 0.93 (95% confidence interval: 0.67, 1.29) for the remaining 20 weeks. CPT was not associated with the other outcomes examined.

CONCLUSIONS

CPT offered temporary protection against malaria among HIV-exposed, uninfected infants. However, CPT offered no protection against anemia, low weight for age or the collapsed outcome of severe illness or death.

Performance of rapid influenza H1N1 diagnostic tests: a meta-analysis

Please cite this paper as: Chu et al. (2011) Performance of rapid influenza H1N1 diagnostic tests: a meta‐analysis. Influenza and Other Respiratory Viruses DOI: 10.1111/j.1750‐2659.2011.00284.x.

Background  Following the outbreaks of 2009 pandemic H1N1 infection, rapid influenza diagnostic tests have been used to detect H1N1 infection. However, no meta‐analysis has been undertaken to assess the diagnostic accuracy when this manuscript was drafted.

Methods  The literature was systematically searched to identify studies that reported the performance of rapid tests. Random effects meta‐analyses were conducted to summarize the overall performance.

Results  Seventeen studies were selected with 1879 cases and 3477 non‐cases. The overall sensitivity and specificity estimates of the rapid tests were 0·51 (95%CI: 0·41, 0·60) and 0·98 (95%CI: 0·94, 0·99). Studies reported heterogeneous sensitivity estimates, ranging from 0·11 to 0·88. If the prevalence was 30%, the overall positive and negative predictive values were 0·94 (95%CI: 0·85, 0·98) and 0·82 (95%CI: 0·79, 0·85). The overall specificities from different manufacturers were comparable, while there were some differences for the overall sensitivity estimates. BinaxNOW had a lower overall sensitivity of 0·39 (95%CI: 0·24, 0·57) compared with all the others (P‐value <0·001), whereas QuickVue had a higher overall sensitivity of 0·57 (95%CI: 0·50, 0·63) compared with all the others (P‐value = 0·005).

Conclusions  Rapid tests have high specificity but low sensitivity and thus limited usefulness.

Evaluating nurses' implementation of an infant-feeding counseling protocol for HIV-infected mothers: The Ban Study in Lilongwe, Malawi

A process evaluation of nurses' implementation of an infant-feeding counseling protocol was conducted for the Breastfeeding, Antiretroviral and Nutrition (BAN) Study, a prevention of mother-to-child transmission of HIV clinical trial in Lilongwe, Malawi. Six trained nurses counseled HIV-infected mothers to exclusively breastfeed for 24 weeks postpartum and to stop breastfeeding within an additional four weeks. Implementation data were collected via direct observations of 123 infant feeding counseling sessions (30 antenatal and 93 postnatal) and interviews with each nurse. Analysis included calculating a percent adherence to checklists and conducting a content analysis for the observation and interview data. Nurses were implementing the protocol at an average adherence level of 90% or above. Although not detailed in the protocol, nurses appropriately counseled mothers on their actual or intended formula milk usage after weaning. Results indicate that nurses implemented the protocol as designed. Results will help to interpret the BAN Study's outcomes.

Modifications of a large HIV prevention clinical trial to fit changing realities: a case study of the Breastfeeding, Antiretroviral, and Nutrition (BAN) protocol in Lilongwe, Malawi

In order to evaluate strategies to reduce HIV transmission through breast milk and optimize both maternal and infant health among HIV-infected women and their infants, we designed and implemented a large, randomized clinical trial in Lilongwe, Malawi. The development of protocols for large, randomized clinical trials is a complicated and lengthy process often requiring alterations to the original research design. Many factors lead to delays and changes, including study site-specific priorities, new scientific information becoming available, the involvement of national and international human subject committees and monitoring boards, and alterations in medical practice and guidance at local, national, and international levels. When planning and implementing a clinical study in a resource-limited setting, additional factors must be taken into account, including local customs and program needs, language and socio-cultural barriers, high background rates of malnutrition and endemic diseases, extreme poverty, lack of personnel, and limited infrastructure. Investigators must be prepared to modify the protocol as necessary in order to ensure participant safety and successful implementation of study procedures. This paper describes the process of designing, implementing, and subsequently modifying the Breastfeeding, Antiretrovirals, and Nutrition, (BAN) Study, a large, on-going, randomized breastfeeding intervention trial of HIV-infected women and their infants conducted at a single-site in Lilongwe, Malawi. We highlight some of the successes, challenges, and lessons learned at different stages during the conduct of the trial.

Correlation between Interferon‐γ Secretion and Cytotoxicity, in Virus‐Specific Memory T Cells

ELISpot and intracellular cytokine staining are replacing the traditional cytolytic ((51)Cr release) assay method in vaccine trials using human immunodeficiency virus (HIV)-1, and it is widely assumed that the number of interferon (IFN)- gamma -secreting T cells is a surrogate for the level of cytolytic activity. Thus, we sought to determine whether the detection of IFN- gamma in CD8(+) T cells correlates with cytolytic ability in vitro. In 29 (69.0%) of 42 HIV-1-seronegative immunocompetent individuals (22 unvaccinated and 20 vaccinated), virus-specific T cell responses recognizing cytomegalovirus, Epstein-Barr virus, and influenza and HIV-1 Gag epitopes were detected by at least 1 assay method (ELISpot, intracellular cytokine staining, and/or (51)Cr release), and 18 (62.1%) of these 29 demonstrated both IFN- gamma secretion and cytolysis. There was strong correlation between the results of IFN- gamma ELISpot and those of IFN- gamma intracellular cytokine staining ( rho =0.88) and between the results of (51)Cr release and those of intracellular cytokine staining ( rho =0.81); although the correlation is not absolute, intracellular cytokine staining can be used--and is superior to ELISpot--as a surrogate for cytolytic assays.

Postnatal transmission of HIV-1 after a maternal short-course zidovudine peripartum regimen in West Africa

BACKGROUND

To assess the postnatal transmission (PT) risk of HIV-1 after a maternal short-course zidovudine regimen in a breastfeeding population.

METHODS

Data were pooled from two trials: ANRS 049a DITRAME (Abidjan, Côte d'Ivoire and Bobo-Dioulasso, Burkina-Faso) and RETROCI (Abidjan). Consenting HIV-1 seropositive women were randomized at 36-38 weeks' gestation between September 1995 and February 1998, to receive oral zidovudine or placebo: one tablet twice daily until delivery, and in DITRAME only, for 7 more days. A PT case was infection in a child with a negative HIV-1 PCR at age >/= 30 days who later became infected as defined by a positive HIV-1 PCR, or if aged >/= 15 months, a positive HIV serology. Cumulative risks (CR) of PT were computed using a competing risk approach with weaning as a competing event.

FINDINGS

At age 24 months, CR for PT were similar in the zidovudine (9.8%, n = 254) and placebo groups (9.1%, n = 225). In a multivariate model of PT risk factors, the treatment effect was not significant, maternal CD4 cell count < 500 x 10(6)/l at entry tripled the hazard compared to women with CD4 cell counts >/= 500 x 10(6)/l [hazard ratio (HR), 3.14; 95% confidence interval (CI), 1.31-7.49] as well as an increased maternal plasma viral load at entry (HR, 2.65 for 1 log(10) increase; CI, 1.75-4.00).

INTERPRETATION

PT occurred at a similar rate between arms and therefore reduced the long-term overall efficacy of this peripartum zidovudine regimen at age 24 months. The higher risk of PT among women with low CD4 cell count emphasizes the importance of identifying interventions to prevent PT for these women.

Twenty-four month efficacy of a maternal short-course zidovudine regimen to prevent mother-to-child transmission of HIV-1 in West Africa

OBJECTIVE

To assess the 24 month efficacy of a maternal short-course zidovudine regimen to prevent mother-to-child transmission (MTCT) of HIV-1 in a breastfeeding population in West Africa.

METHODS

Data were pooled from two clinical trials: DITRAME-ANRS049a conducted in Abidjan, Côte d'Ivoire and Bobo-Dioulasso, Burkina-Faso and RETRO-CI, conducted in Abidjan. Between September 1995 and February 1998, consenting HIV-1-seropositive women were randomly assigned to receive zidovudine (300 mg) or placebo: one tablet twice daily from 36-38 weeks' gestation until delivery, then in DITRAME only, for 7 more days. Paediatric HIV-1 infection was defined as a positive HIV-1 polymerase chain reaction, or if aged > or =15 months, a positive HIV-1 serology. Cumulative risks (CR) of infection were estimated using a competing risk approach with weaning as a competing event.

RESULTS

Among 662 live-born children, 641 had at least one HIV-1 test. All but 12 children were breastfed. At 24 months, overall CR of MTCT were 0.225 in the zidovudine and 0.302 in the placebo group, a 26% significant reduction. Among children born to women with CD4 cell counts < 500/ml at enrollment, CR of MTCT were similar, 0.396 in the zidovudine and 0.413 in the placebo group. Among children born to women with CD4 cell counts > or =500/ml, CR of MTCT were 0.091 in the zidovudine and 0.220 in the placebo group, a significant 59% reduction.

CONCLUSION

A maternal short-course zidovudine regimen reduces MTCT of HIV-1 at age 24 months, despite prolonged breastfeeding. However, efficacy was observed only among women with CD4 cell counts > or =500/ml. New interventions should be considered to prevent MTCT, especially for African women with advanced HIV-1 immunodeficiency.

Safety and immunogenicity of a high-titered canarypox vaccine in combination with rgp120 in a diverse population of HIV-1-uninfected adults: AIDS Vaccine Evaluation Group Protocol 022A

To test the safety and immunogenicity of a high-titered preparation of ALVAC-HIV vCP205 in both high-risk and low-risk persons and to evaluate variations in dosing schedule, we conducted a multicenter, randomized, double-blind trial of this vector in combination with recombinant subunit gp120 in 150 HIV-1-seronegative volunteers. The high-titered ALVAC vaccine was well tolerated; adverse events were minimal and not influenced by dosing. At day 728, the cumulative probability of a cytotoxic T-lymphocyte (CTL) response was 76% (95% confidence interval [CI]: 64%-89%) among volunteers receiving vaccine, and the net amount attributable to vaccination was 50% (CI: 16%; 74%). The net probability of a repeated positive CTL response by day 728 was 50% (CI: 21%; 64%). There was a significant difference in CTL response at day 182 between volunteers who had received four doses versus three doses of vCP205 (42% vs. 24%, p =.052). The CTL response was similar in high-risk volunteers and vaccinia-naive volunteers compared with vaccinia-immune volunteers. Neutralizing antibody responses were detected in 95% of vaccinees at day 287, with higher geometric mean titers in recipients of sequential versus simultaneous dosing of the two vaccines and in vaccinia-naive volunteers. This high-titered preparation of ALVAC-HIV vCP205 in combination with gp120 was safe and immunogenic in a diverse group of HIV-1-seronegative volunteers.

Estimating the efficacy of interventions to prevent mother-to-child transmission of HIV in breast-feeding populations: development of a consensus methodology

Postnatal transmission of HIV through breast milk complicates both the design of effective interventions to prevent mother-to-child transmission of HIV (PMTCT) and their evaluation. Estimated long-term efficacy in five African trials (four with peri-partum antiretrovirals and one with artificial feeding) varied from 25 to 50 per cent. This variation may be due, at least in part, to differences in analytical methodology. To facilitate direct comparison between trials, a methodological consensus approach to the analysis and presentation of the results of PMTCT trials was developed. The initial methodology used and results presented from African trials with available long-term efficacy data were reviewed during a workshop in Bordeaux, France, in September 2000. A consensus approach for evaluating efficacy applicable across PMTCT studies was developed. There are four typical situations defined by duration of follow-up (short versus long), and the available demographic (vital status) and biological data (single versus repeat HIV testing). Efficacy can be assessed from the risk of infection directly or from HIV-free survival by combining infection and death as a single endpoint. Studies should report results in a standardized format including infection, weaning, mortality and loss to follow-up. New statistical methods that account for the unknown date when a child would first test positive for HIV, for weaning as a competing risk for HIV infection, and for increased risk of death among HIV-infected children should be used in analysing data from PMTCT studies with repeat HIV testing. All estimates should be reported with confidence intervals. This standardized methodology that allows direct comparison between studies is now being applied to four randomized clinical trials.