Browsing by Author "Dunning, Lorna"

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    Open Access
    Impact of introducing an HIV-PCR test at birth to attendance at follow-up early infant diagnosis (EID) services for HIV-exposed infants in Cape Town
    (2016) Dunning, Lorna; Myer, Landon
    Introduction: PCR testing at birth ('birth-testing') is conditionally advised by new World Health Organization guidelines for rapid diagnosis of infants infected with HIV in utero. Prompt diagnosis and early introduction of antiretroviral therapy (ART) can dramatically reduce mortality in HIV-infected infants. However, a negative result at birth must be followed by engagement in subsequent routine early infant diagnosis (EID) services (recommended at 6-10 weeks of age) to rule out intra-partum infection. There are few data on the implementation of this approach in sub-Saharan Africa and whether birth-testing affects the uptake of subsequent routine EID testing is unknown. Methods: We conducted a retrospective cohort study using routine clinical and laboratory data from a large obstetric hospital in Cape Town. All infants suspected to be at high risk of HIV-transmission, underwent birthtesting between July 2013-August 2015. Infants with a negative birth-test were matched to HIV-exposed infants who did not receive birth-testing. Maternal antenatal and obstetric characteristics of neonates were abstracted via folder review. Primary outcome was any subsequent HIV-PCR test before the end of follow-up, ascertained from the National Health Laboratory Service database. Data were analyzed using logistic regression models, examining independent predictors of presentation at follow-up EID testing. Results: Overall, 575 neonates underwent birth-testing, with 22 positive (3.8%) and 551 negative results. At follow-up EID presentation (n=871), 4 infected infants were identified (0.4%). Fewer infants who underwent birth-testing presented for later EID compared to infants who did not receive a birth-test (73% vs 85%), (Odds Ratio, 0.46; 95% confidence interval, 0.34-0.62). Infants who underwent birth-testing, also presented for later EID at a significantly older age (mean age 60 days vs.50 days, p<0.001). The significantly lower rate of EID presentation among birth-tested children persisted in multivariable analyses adjusting for maternal age, nadir CD4 cell count, ART use during pregnancy, gestation, infant sex, birthweight and infant feeding modality (Adjusted odds ratio, 0.60 95% confidence interval, 0.40-0.88). Conclusions: Neonates undergoing HIV testing at birth may be less likely to present for subsequent EID testing than those not birth-tested. Emphasis must be placed on appropriate counseling provided to caregivers on the need for further HIV testing after negative birth-test results.
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    Laboratory evaluation of the Alere q point-of-care system for early infant HIV diagnosis
    (Public Library of Science, 2016) Hsiao, Nei-yuan; Dunning, Lorna; Kroon, Max; Myer, Landon
    Introduction Early infant diagnosis (EID) and prompt linkage to care are critical to minimise the high morbidity and mortality associated with infant HIV infection. Attrition in the "EID cascade" is common; however, point-of-care (POC) EID assays with same-day result could facilitate prompt linkage of HIV-infected infant to treatment. Despite a number of POC EID assays in development, few have been independently evaluated and data on new technologies are urgently needed to inform policy. METHODS: We compared Alere q 1/2 Detect POC system laboratory test characteristics with the local standard of care (SOC), Roche CAP/CTM HIV-1 qualitative PCR in an independent laboratory-based evaluation in Cape Town, South Africa. Routinely EID samples collected between November 2013 and September 2014 were each tested by both SOC and POC systems. Repeat testing was done to troubleshoot any discrepancy between POC and SOC results. RESULTS: Overall, 1098 children with a median age of 47 days (IQR, 42-117) were included. Birth PCR (age <7 days) comprised of 8% (n = 92) tests while 56% (n = 620) of children tested as part of routine EID (ages 6-14 weeks). In the overall direct comparison, Alere q Detect achieved sensitivity of 95.5% (95% CI, 91.7-97.9%) and a specificity of 99.8% (95% CI, 99.1-100%). Following repeat testing of discordant samples and exclusion of any inconclusive results, the POC assay sensitivity and specificity were 96.9% (95% CI 93.4-98.9%) and 100% (lower 95% CI 98%) respectively. Among birth PCR tests the POC assay had slightly lower sensitivity (93.3% vs 96.5% in routine EID) and higher assay error rate (10% vs 5% in samples of older children, p = 0.04). CONCLUSION: Our results indicate this POC assay performs well for EID in the laboratory. The high specificity and thus high positive predictive value would suggest a positive POC result may be adequate for immediate infant ART initiation. While POC testing for EID may have particular utility for birth testing at delivery facilities, the lower sensitivity and error rate requires further attention, as does field implementation of POC EID technologies in other clinical care settings.