Diagnosing acute HIV infection: The performance of quantitative HIV-1 RNA testing (viral load) in the 2014 laboratory testing algorithm

Effect of a confirmatory testing algorithm on early acute HIV diagnosis in Korea

ABSTRACT

The 17 Provincial Institutes of Health and Environment (PIHEs) in Korea use HIV antibody, antigen, and Western blot assays for confirmatory testing of HIV infection. The Korea Disease Control and Prevention Agency (KDCA) has further included p24 antigen neutralization and nucleic acid tests (NATs) since 2015. Our study aimed to investigate the effect of this new testing algorithm on the confirmation rate of HIV infection.Annual changes, from 2012 through 2017, in positive or indeterminate HIV confirmatory results were compared for the two algorithms between the PIHEs and the KDCA. Fiebig stages and Western blot p31 band were used to identify the diagnostic proportions of acute or early chronic HIV for the two algorithms.The number of positive cases in the samples requested from PIHEs for reconfirmation by the KDCA has steadily increased from 10.3% in 2014 to 33.3% in 2017. However, the number of indeterminate cases dropped sharply, from 71.9% in 2014 to 14.0% in 2017. The results for the p31 reactive band were 27.4% and 88.4% for the KDCA and PIHEs, respectively. Of positive cases reported by the KDCA, 22.9% were in the early acute stage and Fiebig stages I to II.The new testing algorithm has improved the diagnosis of HIV infections in the early acute stage. Early confirmatory diagnosis can prevent secondary transmission of HIV and provide early treatment opportunities for people living with HIV infection.

Modern diagnostic technologies for HIV

Novel diagnostic technologies, including nanotechnology, microfluidics, -omics science, next-generation sequencing, genomics big data, and machine learning, could contribute to meeting the UNAIDS 95-95-95 targets to end the HIV epidemic by 2030. Novel technologies include multiplexed technologies (including biomarker-based point-of-care tests and molecular platform technologies), biomarker-based combination antibody and antigen technologies, dried-blood-spot testing, and self-testing. Although biomarker-based rapid tests, in particular antibody-based tests, have dominated HIV diagnostics since the development of the first HIV test in the mid-1980s, targets such as nucleic acids and genes are now used in nanomedicine, biosensors, microfluidics, and -omics to enable early diagnosis of HIV. These novel technologies show promise as they are associated with ease of use, high diagnostic accuracy, rapid detection, and the ability to detect HIV-specific markers. Additional clinical and implementation research is needed to generate evidence for use of novel technologies and a public health approach will be required to address clinical and operational challenges to optimise their global deployment.

HIV incidence among pregnant and postpartum women in a high prevalence setting

In sub-Saharan Africa, most women who test HIV negative at the first antenatal care encounter are rarely tested again during pregnancy and postpartum, yet data suggests that pregnancy is associated with increased risk of HIV acquisition compared to non-pregnant women. We describe HIV incidence during pregnancy and postpartum in Lesotho, a high prevalence setting, and factors associated with HIV seroconversion. We enrolled a cohort of HIV negative women presenting at health facilities for antenatal care and followed them through delivery up to 24 months postpartum. Women were repeatedly tested for HIV according to the Lesotho Ministry of Health routine rapid HIV testing guidelines and responded to risk behavior questionnaire every three months. We estimated HIV incidence and associated 95% confidence intervals. We used mixed effects Cox regression models to identify independent factors associated with seroconversion accounting for repeated assessment. The estimated overall HIV incidence rate was 1.58 (95% CI: 1.05-2.28) per 100 person- years. The estimated HIV incidence rate during pregnancy (2.61 per 100 person-years, 95% CI: 1.12-5.14) was almost double the estimated HIV incidence during postpartum (1.36 per 100 person-years, 95% CI: 0.83-2.10). Women's age (14-24 years compared to 25-45 years), multiple sexual partnerships, urethral discharge and no condoms nor pre-exposure prophylaxis were independently associated with HIV infection. There is an increased need for counseling and support of HIV-uninfected pregnant and breastfeeding women to stay HIV-negative, including provision of pre-exposure prophylaxis during this high-risk period, particularly among adolescent and young women.