Evaluation of the Aptima HIV-1 Quant Dx assay for HIV diagnosis at birth in South Africa.

The increased coverage of antiretroviral therapy has resulted in a decrease in the positive predictive value (PPV) and diagnostic sensitivity of early infant diagnosis assays. To evaluate the diagnostic performance of the Aptima HIV-1 Quant DX assay (Aptima) in detecting HIV infection at birth. The study was a cross-sectional laboratory based evaluation using whole blood DBS specimens. Samples were collected from HIV-exposed neonates at birth at two paediatric facilities in Gauteng between 1st March 2018 - 31st January 2020. Performance of the Aptima compared to the Cobas® AmpliPrep/Cobas® TaqMan HIV-1 Qualitative Test v2.0 was calculated using a two-by-two table and reported as proportions with 95% confidence intervals. A total of 363 infants met the inclusion criteria of which 4 (1.1%) had an Aptima result discordant with CAP/CTM HIV status: two (50%) negative and two (50%) positive. The Aptima assay had a sensitivity of 93.75% (95% CI: 79.19%-99.23%), specificity of 99.4% (95% CI: 97.83%-99.93%), PPV of 93.75% (95% CI: 78.98%-98.36%), negative predictive value of 99.4% (95% CI: 97.73%-99.84%), and overall accuracy of 98.9% (95% CI: 97.2%-99.7%). The Aptima yielded an error code on 37 (10.19%) results, of which 35 (94.59%) were resolved on repeat testing. Of the 32 HIV-detected specimens, 20 had a plasma VL result available (18 on Abbott and 2 on Cobas). The absolute median difference was 0.66 log10 (IQR: 0.36-1.71). The Aptima demonstrated good EID performance and can be considered as a qualitative EID assay.

HIV testing at birth: Are we getting it right?

BACKGROUND: Birth polymerase chain reaction (PCR) testing improves early detection of HIV and allows for early treatment initiation. National guidelines exist, but it is unknown whether these are being implemented correctly. OBJECTIVES: To determine whether HIV-exposed infants at the Mangaung University Community Partnership Programme Community Health Centre (MUCPP CHC) received PCR tests at birth, if HIV-positive infants were initiated on treatment, if follow-up dates were scheduled and the percentage of mothers or caregivers who returned to collect the results. METHODS: The study was a retrospective descriptive file audit (1304 files) of births from 01 January to 31 December 2016 at MUCPP CHC. The study sample was 428 infants born to HIV-positive mothers. The birth register was used to collect the infants' HIV PCR test barcodes. The birth and 10-week PCR results were retrieved from an electronic database at the Virology Department, University of the Free State. RESULTS: In total, 375 infants received a birth PCR test (87.6%) of which 4 (1.1%) tested HIV positive and 327 (87.2%) negative. Follow-up tests were not scheduled. However, 145 (44.3%) HIV-negative infants returned for a 10-week test. Irrespective of the PCR birth result, 157 (36.7%) infants were brought for a 10-week follow-up test at which time 3 (1.9%) tested positive and 151 (96.2%) negative. CONCLUSION: The majority of HIV-exposed infants received a PCR test at birth; however, the clinic is below the national target (90%) for HIV testing. A record-keeping system of infants' visits does not exist at MUCPP CHC, making it impossible to determine whether HIV-positive infants were started on antiretroviral treatment.

Neonatal and infant diagnostic HIV-PCR uptake and associations during three sequential policy periods in Cape Town, South Africa: a longitudinal analysis.

INTRODUCTION: To strengthen the early infant diagnosis (EID) programmes and timeously identify and treat HIV-infected infants, birth HIV-PCR for some/all infants has been recommended in the Western Cape, South Africa since 2014. Operational data on the implementation of such programmes in low- and middle-income countries are limited. METHODS: Utilizing the electronic records platform at primary care facilities, we developed an electronic register which consolidated obstetric and HIV-related data, allowing us to track a cohort of HIV-infected/exposed mother/infant dyads longitudinally from antenatal care through delivery to infant HIV-PCR. We assessed guideline implementation and impact on EID of three sequential EID policies in a referral chain of facilities in Cape Town (primary-tertiary care). Birth HIV-PCR was indicated in period 1 if symptomatic; period 2 if meeting high-risk criteria for transmission; and period 3 for all HIV-exposed neonates. RESULTS: We enrolled 2012 HIV-exposed infants; 89.2% had at least one HIV-PCR at any point. The majority of birth tests were performed in hospital versus primary care regardless of policy period. Almost half of all infants (47.9%) had at least one high-risk criterion for vertical infection; of these, 39.7% had a birth test. Infants with more risk factors were more likely to have birth EID. Receipt of a birth HIV-PCR significantly reduced the likelihood of receiving a follow-up test at six to ten weeks, even after adjusting for potential confounders (aOR 0.18 (0.12 to 0.26)). The proportion of infants tested at six to ten weeks old dropped from 92.9% (period 1) to 80.2% in period 3 and those receiving birth HIV-PCR increased, peaking at 67.4% during period 3. The proportion of positive birth tests was highest (2.9%) when birth tests were restricted to infants meeting high-risk criteria, with a low proportion positive for the first time at six to ten weeks. During period 3, the proportion positive at six to ten weeks was high (2.4%), highlighting the importance of follow-up to detect intrapartum and early postpartum infections. CONCLUSIONS: Over all policy periods, EID guidelines were incompletely implemented across all levels of care but especially in primary care. Birth HIV-PCR reduced return for follow-up testing, such follow-up testing is critical for the effectiveness of the programme.