Bharat Parekh

• Doctor of Philosophy
• Group Leader at Centers for Disease Control and Prevention

HIV cross-sectional surveys require multi-layered testing with several tests to estimate HIV prevalence and HIV-1 incidence. We evaluated the performance and accuracy of the newly developed HIV Triplex assay to diagnose HIV-1 and HIV-2 and detect HIV-1 recent infections using plasma samples from the 2018 Nigeria AIDS Indicator and Impact Survey (NA...

Background: A recent infection testing algorithm (RITA) incorporating case surveillance (CS) with the rapid test for recent HIV infection (RTRI) was integrated into HIV testing services in Thailand as a small-scale pilot project in October 2020. Objective: We aimed to describe the lessons learned and initial outcomes obtained after the establishmen...

Background We developed the HIV Triplex multiplex bead assay to identify and serotype HIV infection with high sensitivity and specificity; and distinguish recent from long-term HIV-1 infections. It can facilitate accurate incidence estimation, while reducing the number of tests and blood collected, which is highly desirable for use in future studie...

During population-based HIV impact assessments (PHIAs), some participants who self-reported testing HIV-positive (PSRP) tested negative in one or more subsequent survey HIV tests. These unexpected discrepancies between their self-reported results and the survey results draw into question the validity of either the self-reported status or the test r...

BACKGROUND A recent infection testing algorithm (RITA) incorporating case surveillance (CS) with the rapid test for recent HIV infection (RTRI) was integrated into HIV testing services in Thailand. OBJECTIVE To describe the establishment of the recent HIV infection surveillance and report lessons learned and initial outcomes from April through Aug...

Background A recent infection testing algorithm (RITA) incorporating case surveillance (CS) with the rapid test for recent HIV infection (RTRI) was integrated into HIV testing services in Thailand as a small-scale pilot project in October 2020. Objective We aimed to describe the lessons learned and initial outcomes obtained after the establishment...

The Sedia Biosciences Asanté rapid test for recent infection (RTRI) can identify HIV infections and characterize HIV-1 as recent or long-term infection via the positive verification (V) line and long-term line (LT) line, respectively. Tracking with Recency Assays to Control the Epidemic (TRACE) program uses RTRI assays. Successful implementation of...

Background: HIV testing is a critical step to accessing antiretroviral therapy (ART) because early diagnosis can facilitate earlier initiation of ART. This study presents aggregated data of individuals who self-reported being HIV-positive but subsequently tested HIV-negative during nationally representative Population-Based HIV Impact Assessment s...

Identifying persons who have newly acquired HIV infections is critical for characterizing the HIV epidemic direction. We analyzed pooled data from nationally representative Population-Based HIV Impact Assessment surveys conducted across 14 countries in Africa for recent infection risk factors. We included adults 15-49 years of age who had sex durin...

[This corrects the article DOI: 10.1371/journal.pgph.0000316.].

Background: In 2014, UNAIDS set the goal of ending the AIDS epidemic by 2030 through the achievement of testing and treatment cascade targets. To evaluate progress achieved and highlight persisting gaps in HIV epidemic control in Malawi, we aimed to compare key indicators (prevalence, incidence, viral load suppression, and UNAIDS 95-95-95 targets)...

Background We examined the epidemiology and transmission potential of HIV population viral load (VL) in 12 sub-Saharan African countries. Methods We analyzed data from Population-based HIV Impact Assessments (PHIAs), large national household-based surveys conducted between 2015 and 2019 in Cameroon, Cote d’Ivoire, Eswatini, Kenya, Lesotho, Malawi,...

Population-based HIV Impact Assessments (PHIAs) are national household (HH) surveys that provide HIV diagnosis and CD4 testing with an immediate return of results. Accurate CD4 results improve HIV-positive participants’ clinical care and inform the effectiveness of HIV programs. Here, we present CD4 results from the PHIA surveys that were conducted...

Background: Estimating HIV-1 incidence using biomarker assays in cross-sectional surveys is important for understanding the HIV pandemic. However, the utility of these estimates has been limited by uncertainty about what input parameters to use for false recency rate (FRR) and mean duration of recent infection (MDRI) after applying a recent infect...

The HIV epidemic is still one of the world’s most serious public health challenges, affecting about 38 million people worldwide, especially in sub-Saharan African and Southeast Asian countries. In recent years, tests have been developed to discriminate recent from long-term infection in HIV-infected populations, and these tools can help identify ne...

Standard-of-care HIV pre-exposure prophylaxis (PrEP) is highly efficacious, but uptake of and persistence on a daily oral pill is low in many settings. Evaluation of alternate PrEP products will require innovation to avoid the unpractically large sample sizes in noninferiority trials. We propose estimating HIV incidence in people not on PrEP as an...

Background: Nationally-representative surveys provide an opportunity to assess trends in recent HIV infection based on assays for recent HIV infection. Methods: We assessed HIV incidence in Kenya in 2018 and trends in recent HIV infection among adolescents and adults in Kenya using nationally representative household surveys conducted in 2007, 2...

Background: Estimating HIV incidence is essential to monitoring progress in sub-Saharan African nations toward global epidemic control. One method for incidence estimation is to test nationally-representative samples using laboratory-based incidence assays. An alternative method based on reported HIV testing history and the proportion of undiagnos...

Human Immunodeficiency Virus (HIV) diagnosis remains the gateway to HIV care and treatment. However, due to changes in HIV prevalence and testing coverage across different geopolitical zones, it is crucial to evaluate the national HIV testing algorithm as false positivity due to low prevalence could be detrimental to both the client and the service...

Background Data on awareness of HIV status among people living with HIV (PLHIV) are critical to estimating progress toward epidemic control. To ascertain the accuracy of self-reported HIV status and antiretroviral drug (ARV) use in the Nigeria HIV/AIDS Indicator and Impact Survey (NAIIS), we compared self-reported HIV status with HIV rapid diagnost...

Background The Nigeria AIDS Indicator and Impact Survey (NAIIS), a cross-sectional household survey, was conducted in 2018 with primary objectives to estimate HIV prevalence, HIV-1 incidence, and status of UNAIDS 90-90-90 cascade. We conducted retrospective analysis of the performance of HIV rapid tests and the national HIV testing algorithm used i...

Despite extensive global efforts, sub-Saharan Africa remains disproportionately affected by the HIV epidemic. This generalized epidemic can be seen in Lesotho which in 2014 the HIV prevalence rate of those aged 15–49 years was 24.6%, with and incidence of 1.9 new infections per 100-person-year exposures. To better understand the impact of Lesotho’s...

Following publication of the original article [1], the authors identified an error in the affiliations stated for the last author, Salem Gugsa. At the time of the manuscript development, the author’s affiliation was assigned to 3 instead of 4. The affiliations assignment is corrected in the author list of this Correction article and the original ar...

We previously described development of a rapid test for recent infection (RTRI) that can diagnose HIV infection and detect HIV-1 recent infections in a single device. This technology was transferred to a commercial partner as Asante Rapid Recency Assay (ARRA). We evaluated performance of the ARRA kits in the laboratory using a well-characterized pa...

Diagnostic assays that can simultaneously determine the presence of infection with multiple pathogens are key for diagnosis and surveillance. Current multiplex diagnostic assays are complex and often have limited availability. We developed a simple, multianalyte, pathogen detection assay for screening and serosurveillance using the Luminex Magpix p...

Estimating HIV-1 incidence using biomarker assays in cross-sectional surveys is important for understanding the HIV pandemic. However, the utility of these estimates has been limited by uncertainty about what input parameters to use for False Recency Rate (FRR) and Mean Duration of Recent Infection (MDRI) after applying recent infection testing alg...

Background The Malawi Ministry of Health implemented a new surveillance activity in April 2019 to detect recent HIV infections using a rapid test for recent infection (RTRI) to identify areas of ongoing transmission and guide response activities. Setting At 23 health facilities in Blantyre District, healthcare workers (HCWs) were trained to conduc...

Persons infected with HIV are more likely to transmit the virus during the early stages (acute and recent) of infection, when viral load is elevated and opportunities to implement risk reduction are limited because persons are typically unaware of their status (1,2). Identifying recent HIV infections (acquired within the preceding 12 months)* is cr...

Introduction Late diagnosis of HIV (LD) increases the risk of morbidity, mortality, and HIV transmission. We used nationally representative data from population-based HIV impact assessment (PHIA) surveys in Malawi, Zambia, and Zimbabwe (2015–2016) to characterize adults at risk of LD and to examine associations between LD and presumed HIV transmiss...

Tests for recent HIV infection (TRI) distinguish recent from long-term HIV infections using markers of antibody maturation. The limiting antigen avidity enzyme immunoassay (LAg EIA) is widely used with HIV viral load (VL) in a recent infection testing algorithm (RITA) to improve classification of recent infection status, estimate population-level H...

With the highest HIV incidence and prevalence globally, the government of Eswatini started a substantial scale-up of HIV treatment and prevention services in 2011. Two sequential large population-based surveys were conducted before and after service expansion to assess the impact of the national response. Cross-sectional, household-based, nationall...

Background: HIV-1 incidence calculation currently includes recency classification by HIV-1 incidence assay and unsuppressed viral load (VL ≥ 1000 copies/mL) in a recent infection testing algorithm (RITA). However, persons with recent classification not virally suppressed and taking antiretroviral (ARV) medication may be misclassified. Setting: W...

Background: The need for accurate HIV annual program planning data motivated the compressed timeline for the 2018 Nigerian HIV/AIDS Indicator and Impact Survey (NAIIS). The survey team used stakeholder cooperation and responsive design, using survey process and paradata to refine survey implementation, to quickly collect high-quality data. We desc...

Objective: We present findings from the nationally representative Zimbabwe Population-based HIV Impact Assessment (ZIMPHIA) that characterize Zimbabwe's progress toward the Joint United Nations Programme on HIV/AIDS 90-90-90 targets. Design: We conducted a cross-sectional household survey. Methods: Consenting adults and children in the household...

Background: Conducting HIV surveys in resource-limited settings is challenging because of logistics, limited availability of trained personnel, and complexity of testing. We described the procedures and systems deemed critical to ensure high-quality laboratory data in the population-based HIV impact assessments and large-scale household surveys. M...

Background: In the population-based HIV impact assessment surveys, early infant diagnosis (EID) was provided to infants <18 months without a prior diagnosis. For the Namibia population-based HIV impact assessment (NAMPHIA), the GeneXpert platform was assessed for the feasibility of near POC EID testing compared with the standard Roche COBAS AmpliP...

Background: The population-based HIV impact assessment (population-based HIV impact assessments) surveys are among the first to estimate national adult HIV incidence, subnational prevalence of viral load suppression, and pediatric HIV prevalence. We summarize the survey methods implemented in Zimbabwe, Malawi, and Zambia, as well as response rates...

Introduction New HIV infection during pre-conception and pregnancy is a significant contributor of mother–to–child transmission of HIV in South Africa. This study estimated HIV incidence (defined as new infection within the last one year from the time of the survey which included both new infections occurred during pregnancy or just before pregnanc...

Background: Male circumcision (MC) offers men lifelong partial protection from heterosexually-acquired HIV infection. The impact of MC on HIV incidence has not been quantified in nationally-representative samples. Data from the Population-based HIV Impact Assessments (PHIAs) were used to compare incidence by MC status in countries implementing vol...

The World Health Organization and national guidelines recommend HIV testing and counseling at tuberculosis (TB) clinics for all patients, regardless of TB diagnosis (1). Population-based HIV Impact Assessment (PHIA) survey data for 2015-2016 in Malawi, Zambia, and Zimbabwe were analyzed to assess HIV screening at TB clinics among persons who had po...

Background: HIV population viral load (PVL) can reflect antiretroviral therapy (ART) program effectiveness and transmission potential in a community. Using nationally representative data from household surveys conducted in Zimbabwe, Malawi, and Zambia in 2015-16, we examined the association between various VL measures and the probability of at lea...

Introduction: The global target for 2020 is that ≥90% of people living with HIV (PLHIV) receiving antiretroviral therapy (ART) will achieve viral load suppression (VLS). We examined VLS and its determinants among adults receiving ART for at least four months. Methods: We analysed data from the population-based HIV impact assessment (PHIA) surveys...

The Mozambique Indicators of Immunization, Malaria and HIV/AIDS (IMASIDA) survey was conducted in 2015 and used a two Enzyme Immunoassay (EIA) (Vironostika HIV-1/2 and Murex HIV-1/2) based algorithm to determine the HIV status of the consented participants. The Mozambique Ministry of Health, with support from the US Centers for Disease Control and...

The Mozambique Indicators of Immunization, Malaria and HIV/AIDS (IMASIDA) survey was conducted in 2015 and used a two Enzyme Immunoassay (EIA) (Vironostika HIV-1/2 and Murex HIV-1/2) based algorithm to determine the HIV status of the consented participants. The Mozambique Ministry of Health, with support from the US Centers for Disease Control and...

Introduction: The Joint United Nations Programme on HIV/AIDS (UNAIDS) has set a target of ≥90% of people living with HIV (PLHIV) receiving antiretroviral therapy (ART) to have viral load suppression (VLS). We examined factors associated with nonsuppressed viral Load (NVL). Methods: We included PLHIV receiving ART aged 15-59 years from Eswatini, Les...

Background As Zimbabwe approaches epidemic control of HIV, programs now prioritize viral load over CD4 monitoring, making it difficult to identify persons living with HIV (PLHIV) suffering from advanced disease (AD). We present an analysis of cross-sectional ZIMPHIA data, highlighting PLHIV with AD and concurrent viral load suppression (VLS). Meth...

Background: Zimbabwe conducted a Population-Based HIV Impact Assessment (ZIMPHIA) cross-sectional survey, October 2015 and August 2016 to determine progress toward epidemic control. Methods: Of 25,131 eligible adults 15-64 years, 20,577 (81.8%) consented to face-to-face questionnaire and biomarker testing in this nationally representative househ...

A 2014 report evaluating accuracy of serologic testing for transfusion-transmissible viruses at African blood center laboratories found sensitivities of 92%, 87%, and 90% for detecting infections with human immunodeficiency virus (HIV), hepatitis B virus (HBV), and hepatitis C virus (HCV), respectively (1). Following substantial investments in nati...

Objective This is the first large-scale assessment of the implementation of HIV Rapid Test Quality Improvement Initiative in South Africa. Methods We used a quasi-experimental one group post-test only design. The intervention implemented starting April 2014 comprised health-care worker training on quality assurance (QA) of HIV rapid testing and en...

Background: HIV acquisition remains high among adolescent girls and young women (AGYW, aged 15-24 years) in sub-Saharan Africa. We aimed to estimate prevalence and incidence of HIV in AGYW and to identify correlates of HIV infection by using data from the Lesotho Population-based HIV Impact Assessment (LePHIA). Methods: LePHIA was a nationally r...

Objective: The Lesotho Population-based HIV Impact Assessment (LePHIA) survey was conducted nationally and designed to measure HIV prevalence, incidence, and viral load suppression (VLS). Design: A nationally representative sample of 9,403 eligible households was surveyed between November 2016 and May 2017; analyses account for study design. Con...

Introduction HIV misdiagnosis leads to severe individual and public health consequences. Retesting for verification of all HIV-positive cases prior to antiretroviral therapy initiation can reduce HIV misdiagnosis, yet this practice has not been not widely implemented. Methods We evaluated and compared the cost of retesting for verification of HIV...

A 2014 report revealed sensitivities of 92%, 87% and 90% to anti-HIV, HBsAg and anti-HCV, respectively, at African blood center laboratories but substantial international investments in national blood transfusion services (NBTS) have since been made. During 2017, we performed a proficiency testing study at 84 blood center laboratories in seven Afri...

Reliable and accurate laboratory assays to detect recent HIV-1 infection have potential as simple and practical methods of estimating HIV-1 incidence in cross-sectional surveys. This study describes validation of the limiting-antigen (LAg) avidity enzyme immunoassay (EIA) in a cross-sectional national survey, conducted in Swaziland, comparing it to...

Biomarkers for detecting early HIV infection and estimating HIV incidence should minimize false-recent rates (FRRs) while maximizing mean duration of recent infection (MDRI). We compared HIV subtypes B, E and D (BED) capture enzyme immunoassay (BED), Sedia limiting antigen (LAg) avidity enzyme immunoassay, and Bio-Rad avidity incidence (BRAI) assay...

Background A previous analysis of the impact of drought in Africa on HIV demonstrated an 11% greater prevalence in HIV-endemic rural areas attributable to local rainfall shocks. The Lesotho Population-Based HIV Impact Assessment (LePHIA) was conducted after the severe drought of 2014–2016, allowing for reevaluation of this relationship in a setting...

LePHIA adult questionnaire. (PDF)

Project concept analysis plan. (DOCX)

In 2017, rapid human immunodeficiency virus (HIV) testing services enabled the HIV diagnosis and treatment of approximately 15.3 million persons with HIV infection in sub-Saharan Africa with life-saving antiretroviral therapy (ART) (1). Although suboptimal testing practices and misdiagnoses have been reported in sub-Saharan Africa and elsewhere, tr...

HIV diagnostics have played a central role in the remarkable progress in identifying, staging, initiating, and monitoring infected individuals on life-saving antiretroviral therapy. They are also useful in surveillance and outbreak responses, allowing for assessment of disease burden and identification of vulnerable populations and transmission “ho...

As part of the global response to the HIV/AIDS epidemic, the U.S. President's Emergency Plan for AIDS Relief (PEPFAR) is committed to the provision of high‐quality services and ensuring testing accuracy. Two recently published papers focusing on HIV testing and misdiagnosis in sub‐Saharan Africa by Kosack et al. report on evaluations of HIV rapid d...

Laboratory assays that can accurately distinguish recent (occurring within the past year) from long-standing (>1 year) HIV infection are crucial for understanding HIV transmission dynamics in a population. However, often these efforts are confounded by inaccurate HIV diagnosis and the presence of HIV-2 in the population being surveyed. This study d...

View the 2017 Expert Summit program "From Care to Cure: Shifting the HIV Paradigm", held in Barbados Aug 27-31 2017, on which the conference proceedings published in AID Research and Human Retroviruses are based

View the 2018 CCAS Expert Summit announcement "From Care to Cure: Towards the Elimination of HIV", to be held in St. Lucia August 26-30 2018.

The CCAS EXPERT SUMMIT convened an array of international experts in Barbados on August 27-31 2017 under the theme "From Care to Cure - Shifting the HIV Paradigm". The Caribbean Cytometry & Analytical Society (CCAS) partnered with the Joint United Nations Programme on HIV/AIDS (UNAIDS) to deliver a program that reviewed the advances in antiretrovir...

In 2016, an estimated 1.5 million females aged 15-24 years were living with human immunodeficiency virus (HIV) infection in Eastern and Southern Africa, where the prevalence of HIV infection among adolescent girls and young women (3.4%) is more than double that for males in the same age range (1.6%) (1). Progress was assessed toward the Joint Unite...

Introduction: Logistical complexities of returning laboratory test results to participants have precluded most population-based HIV surveys conducted in sub-Saharan Africa from doing so. For HIV positive participants, this presents a missed opportunity for engagement into clinical care and improvement in health outcomes. The Population-based HIV I...

Introduction Dual HIV/syphilis rapid diagnostic tests (RDTs) may prevent congenital syphilis by facilitating syphilis diagnosis in pregnant women receiving HIV testing. The dual HIV-1/2 treponemal syphilis RDT (Chembio DPP HIV-Syphilis Assay) performs well in the lab, but its field performance is unknown. We investigated test performance under fiel...

Background: Laboratory assays that identify recent HIV infections are important for assessing impacts of interventions aimed at reducing HIV incidence. Kinetics of HIV humoral responses can vary with inherent assay properties, and between HIV subtypes, populations and physiological states. They are important in determining mean duration of recent...

Background: Laboratory tests that can distinguish recent from long-term HIV infection are used to estimate HIV incidence in a population but can potentially misclassify a proportion of long-term HIV infections as recent. Correct application of an assay requires determination of the proportion false recents (PFR) as part of the assay characterizati...

Background: Swaziland has the highest national HIV prevalence worldwide. The Swaziland HIV Incidence Measurement Survey (SHIMS) provides the first national HIV incidence estimate based on prospectively observed HIV seroconversions. Methods: A two-stage survey sampling design was used to select a nationally representative sample of men and women...

Introduction A recent infection testing algorithm (RITA) that can distinguish recent from long-standing HIV infection can be applied to nationally representative population-based surveys to characterize and identify risk factors for recent infection in a country. Materials and Methods We applied a RITA using the Limiting Antigen Avidity Enzyme Imm...

KAIS Analysis and Publication Concept Sheet Template. (DOCX)

In 2008 HIV rapid testing (HIV RT) was only minimally used in the Caribbean region. Collaboration with countries and international partners since then has resulted in greater availability and use of HIV RT services. Surveys were conducted in 2012 and 2014 among 11 selected Caribbean countries to inform stakeholders of progress made since 2008 and t...

HIV incidence estimates are used to monitor HIV-1 infection in the United States. Use of laboratory biomarkers that distinguish recent from longstanding infection to quantify HIV incidence rely on having accurate knowledge of the average time that individuals spend in a transient state of recent infection between seroconversion and reaching a speci...

Spreadsheet with BED OD values at times since estimated time of seroconversion, assayed for 858 specimens from 209 HIV-1 subtype B seroconverters, taken from 4 data cohorts. (XLSX)

Spreadsheet with Bio-Rad avidity values at times since estimated time of seroconversion, assayed for 749 specimens from 162 HIV-1 subtype B seroconverters, taken from 3 data cohorts. (XLSX)

Four HIV rapid tests were subjected to field validation in Panama and compared to an enzyme-linked immunosorbent assay/ Multispot-based testing algorithm. The sensitivities of Determine, Uni-Gold, SD Bioline, and INSTI were 99.8%. The specificities of Determine, SD-Bioline, and Uni-Gold were 100%, and the specificity of INSTI was 99.8%. On the basi...