CROI 2016 Abstract eBook

Abstract Listing

Poster Abstracts

785 Low Uptake of Routine Infant Diagnostic Testing Following HIV PCR Testing at Birth Jean Maritz 1 ; Nei-Yuan Hsiao 2 ;Wolfgang Preiser 1 ; Landon Myer 2 1 Stellenbosch Univ, Cape Town, South Africa; 2 Univ of Cape Town, Cape Town, South Africa

Background: There is growing emphasis on testing HIV-exposed infants at birth to detect intrauterine infections. However concerns have been raised that implementation of birth testing may reduce uptake of routine early infant diagnostic testing (EID) at around 6 weeks of age. As there are no data on this question, we examined the association between birth PCR and subsequent routine EID testing in the Western Cape province of South Africa (SA), a setting where 6-week EID test coverage is estimated to reach >70% of all HIV-exposed infants. Methods: Data on all HIV PCR tests conducted in the province (approximately 14 000 per year) were accessed from the SA National Health Laboratory Service. Infants with birth PCR (defined as testing in the first 7 days of life) and subsequent EID testing (8 to 182 days of age) were linked probabilistically using Finegrained Record Integration and Linkage Tool (Atlanta, USA); a range of sensitivity analyses were used to maximise linkage of birth tests to subsequent EID testing. Two periods of birth testing policies were compared: discretionary testing by clinicians (DT; Jan 2009- March 2014) and testing of all ‘high risk’ pregnancies based on duration of maternal ART, documented HIV viraemia, and related factors (HR; April 2014-June 2015). Results: Overall 3322 newborns received birth testing (80%within three days of life), comprising 3% of all HIV PCR tests conducted in infants. The number of tests increased >20-fold after the start of HR testing policies. Throughout most birth tests were undertaken in obstetric hospitals, though the proportion of birth tests from primary care facilities increased from 11% under DT to 33% under HR testing (Table). Birth PCR positivity rates decreased from 6% in 2009 to 1.6% in 2015 (p=0.001). Of children with negative birth PCR results, only 49% had any evidence of a follow-up EID test. This proportion decreased to 43%when restricted to a window around prescribed EID testing, but was stable over time with no difference in follow-up testing rates or mean age at retesting under DT vs HR testing policies (p=0.506 and 0.112, respectively). Conclusions: Changing birth testing policies have led to dramatic increases in birth tests. However follow-up EID resting rates in infants testing PCR negative at birth are substantially lower than local estimates of 6-week EID coverage. These data suggest that implementation of birth testing will require particular care to avoid undermining postpartum EID services.

786 The Value of Confirmatory Testing in Early Infant HIV Diagnosis (EID) Programs Andrea L. Ciaranello 1 ; Jordan A. Francke 1 ; Divya Mallampati 2 ; Rachel L. MacLean 1 ; Martina Penazzato 3 ;Taige Hou 1 ; Landon Myer 4 ; Elaine J. Abrams 5 ; Rochelle P.Walensky 1 ; Kenneth A. Freedberg 1 1 Massachusetts General Hosp, Boston, MA, USA; 2 McGawMed Cntr of Northwestern Univ, Chicago, IL, USA; 3 WHO, Geneva, Switzerland; 4 Univ of Cape Town, Cape Town, South Africa; 5 ICAP, Columbia Univ Mailman Sch of PH, New York, NY, USA Background: EID assays have high specificity, but positive predictive value is poor when MTCT risk is low. HIV-infected infants treated with ART may lose detectable antibody, RNA, and DNA. Uninfected infants who start ART after false positive (FP) results are therefore difficult to identify. Confirmatory testing is recommended to avoid ART in uninfected infants; while common in South Africa, it is not routine in many settings. We projected clinical outcomes, FP (incorrect) ART initiations, costs, and cost-effectiveness of EID programs with and without confirmatory testing. Methods: We used the CEPAC-Pediatric model to simulate 6-week EID testing for a cohort of infants born to HIV-infected mothers. We used clinical, cost, and EID assay data from South Africa, as an example (laboratory-based nucleic acid assay: specificity 98.8%; result-return time 1 month; cost $25). We simulated no EID (comparator), EID with confirmation (ART initiation immediately after first positive test; cessation if negative confirmatory test), and EID without confirmation (ART initiation after single positive test). For uninfected infants with FP results, we assumed 25 years of HIV care and ART, and excluded toxicity and stigma. We calculated incremental cost-effectiveness ratios (ICERs) in $/year of life saved (YLS). Results: Projected MTCT risk at 6 weeks of age was 3.0%. EID programs with confirmation markedly increased life expectancy for HIV-infected infants, from 21.1 years (no EID) to 26.3 years (Table). Of every 1000 ART initiations, 6 were FP, accounting for 0.2% of cohort lifetime HIV care costs (total lifetime costs: $1,770/infant tested). The ICER of EID with confirmation compared to no EID was $1,200/YLS (<0.2x South Africa’s per-capita GDP of $6,500). EID without confirmation led to similar clinical outcomes, but at greater lifetime costs ($2,090/infant tested); 297 of every 1000 ART initiations were FP, accounting for 14.3% of lifetime HIV care costs. Results were sensitive to assay specificity, MTCT risk, ART delay for confirmatory testing, and duration of ART after FP results. Conclusions: Without confirmatory EID testing, nearly 30% of infants testing positive and initiating ART could be truly HIV-uninfected in low-MTCT settings, and care for FP infants could comprise a substantial fraction of HIV program costs. Confirmation of positive EID results is cost-saving compared to EID without confirmation in South Africa, and is critical before ART initiation in all settings.

Poster Abstracts

328

CROI 2016