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The value of confirmatory testing in early infant HIV diagnosis programmes in South Africa: A cost-effectiveness analysis.

ABSTRACT: BACKGROUND:The specificity of nucleic acid amplification tests (NAATs) used for early infant diagnosis (EID) of HIV infection is <100%, leading some HIV-uninfected infants to be incorrectly identified as HIV-infected. The World Health Organization recommends that infants undergo a second NAAT to confirm any positive test result, but implementation is limited. Our objective was to determine the impact and cost-effectiveness of confirmatory HIV testing for EID programmes in South Africa. METHOD AND FINDINGS:Using the Cost-effectiveness of Preventing AIDS Complications (CEPAC)-Pediatric model, we simulated EID testing at age 6 weeks for HIV-exposed infants without and with confirmatory testing. We assumed a NAAT cost of US$25, NAAT specificity of 99.6%, NAAT sensitivity of 100% for infants infected in pregnancy or at least 4 weeks prior to testing, and a mother-to-child transmission (MTCT) rate at 12 months of 4.9%; we simulated guideline-concordant rates of testing uptake, result return, and antiretroviral therapy (ART) initiation (100%). After diagnosis, infants were linked to and retained in care for 10 years (false-positive) or lifelong (true-positive). All parameters were varied widely in sensitivity analyses. Outcomes included number of infants with false-positive diagnoses linked to ART per 1,000 ART initiations, life expectancy (LE, in years) and per-person lifetime HIV-related healthcare costs. Both without and with confirmatory testing, LE was 26.2 years for HIV-infected infants and 61.4 years for all HIV-exposed infants; clinical outcomes for truly infected infants did not differ by strategy. Without confirmatory testing, 128/1,000 ART initiations were false-positive diagnoses; with confirmatory testing, 1/1,000 ART initiations were false-positive diagnoses. Because confirmatory testing averted costly HIV care and ART in truly HIV-uninfected infants, it was cost-saving: total cost US$1,790/infant tested, compared to US$1,830/infant tested without confirmatory testing. Confirmatory testing remained cost-saving unless NAAT cost exceeded US$400 or the HIV-uninfected status of infants incorrectly identified as infected was ascertained and ART stopped within 3 months of starting. Limitations include uncertainty in the data used in the model, which we examined with sensitivity and uncertainty analyses. We also excluded clinical harms to HIV-uninfected infants incorrectly treated with ART after false-positive diagnosis (e.g., medication toxicities); including these outcomes would further increase the value of confirmatory testing. CONCLUSIONS:Without confirmatory testing, in settings with MTCT rates similar to that of South Africa, more than 10% of infants who initiate ART may reflect false-positive diagnoses. Confirmatory testing prevents inappropriate HIV diagnosis, is cost-saving, and should be adopted in all EID programmes.

SUBMITTER: Dunning L

PROVIDER: S-EPMC5697827 | biostudies-literature | 2017 Nov

REPOSITORIES: biostudies-literature

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The value of confirmatory testing in early infant HIV diagnosis programmes in South Africa: A cost-effectiveness analysis.

Dunning Lorna L Francke Jordan A JA Mallampati Divya D MacLean Rachel L RL Penazzato Martina M Hou Taige T Myer Landon L Abrams Elaine J EJ Walensky Rochelle P RP Leroy Valériane V Freedberg Kenneth A KA Ciaranello Andrea A

PLoS medicine 20171121 11

<h4>Background</h4>The specificity of nucleic acid amplification tests (NAATs) used for early infant diagnosis (EID) of HIV infection is <100%, leading some HIV-uninfected infants to be incorrectly identified as HIV-infected. The World Health Organization recommends that infants undergo a second NAAT to confirm any positive test result, but implementation is limited. Our objective was to determine the impact and cost-effectiveness of confirmatory HIV testing for EID programmes in South Africa.<h ...[more]

PMID: 29161262

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Project description:IntroductionAs prevalence of undiagnosed HIV declines, it is unclear whether testing programmes will be cost-effective. To guide their HIV testing programmes, countries require appropriate metrics that can be measured. The cost-per-diagnosis is potentially a useful metric.MethodsWe simulated a series of setting-scenarios for adult HIV epidemics and ART programmes typical of settings in southern Africa using an individual-based model and projected forward from 2018 under two policies: (i) a minimum package of "core" testing (i.e. testing in pregnant women, for diagnosis of symptoms, in sex workers, and in men coming forward for circumcision) is conducted, and (ii) core-testing as above plus additional testing beyond this ("additional-testing"), for which we specify different rates of testing and various degrees to which those with HIV are more likely to test than those without HIV. We also considered a plausible range of unit test costs. The aim was to assess the relationship between cost-per-diagnosis and the incremental cost-effectiveness ratio (ICER) of the additional-testing policy. The discount rate used in the base case was 3% per annum (costs in 2018 U.S. dollars).ResultsThere was a strong graded relationship between the cost-per-diagnosis and the ICER. Overall, the ICER was below $500 per-DALY-averted (the cost-effectiveness threshold used in primary analysis) so long as the cost-per-diagnosis was below $315. This threshold cost-per-diagnosis was similar according to epidemic and programmatic features including the prevalence of undiagnosed HIV, the HIV incidence and a measure of HIV programme quality (the proportion of HIV diagnosed people having a viral load <1000 copies/mL). However, restricting to women, additional-testing did not appear cost-effective even at a cost-per-diagnosis of below $50, while restricting to men additional-testing was cost-effective up to a cost-per-diagnosis of $585. The threshold cost per diagnosis for testing in men to be cost-effective fell to $256 when the cost-effectiveness threshold was $300 instead of $500, and to $81 when considering a discount rate of 10% per annum.ConclusionsFor testing programmes in low-income settings in southern African there is an extremely strong relationship between the cost-per-diagnosis and the cost-per-DALY averted, indicating that the cost-per-diagnosis can be used to monitor the cost-effectiveness of testing programmes.

Project description:BackgroundTuberculosis remains the leading cause of death in South Africa. A number of potential new TB vaccine candidates have been identified and are currently in clinical trials. One such candidate is MVA85A. This study aimed to estimate the cost-effectiveness of adding the MVA85A vaccine as a booster to the BCG vaccine in children from the perspective of the South African government.MethodsThe cost-effectiveness was assessed by employing Decision Analytic Modelling, through the use of a Markov model. The model compared the existing strategy of BCG vaccination to a new strategy in which infants receive BCG and a booster vaccine, MVA85A, at 4 months of age. The costs and outcomes of the two strategies are estimated through modelling the vaccination of a hypothetical cohort of newborns and following them from birth through to 10 years of age, employing 6-monthly cycles.ResultsThe results of the cost-effectiveness analysis indicate that the MVA85A strategy is both more costly and more effective - there are fewer TB cases and deaths from TB than BCG alone. The South African government would need to spend an additional USD 1,105 for every additional TB case averted and USD 284,017 for every additional TB death averted. The threshold analysis shows that, if the efficacy of the MVA85A vaccine was 41.3% (instead of the current efficacy of 17.3%), the two strategies would have the same cost but more cases of TB and more deaths from TB would be prevented by adding the MVA85A vaccine to the BCG vaccine. In this case, the government chould consider the MVA85A strategy.ConclusionsAt the current level of efficacy, the MVA85A vaccine is neither effective nor cost-effective and, therefore, not a good use of limited resources. Nevertheless, this study contributes to developing a standardized Markov model, which could be used, in the future, to estimate the potential cost-effectiveness of new TB vaccines compared to the BCG vaccine, in children between the ages of 0-10 years. It also provides an indicative threshold of vaccine efficacy, which could guide future development.

Project description:BackgroundPoor engagement in postpartum maternal HIV care is a challenge worldwide and contributes to adverse maternal outcomes and vertical transmission. Our objective was to project the clinical and economic impact of integrated postpartum maternal antiretroviral therapy (ART) and pediatric care in South Africa.MethodsUsing the CEPAC computer simulation models, parameterized with data from the Maternal and Child Health-Antiretroviral Therapy (MCH-ART) randomized controlled trial, we evaluated the cost-effectiveness of integrated postpartum care for women initiating ART in pregnancy and their children. We compared two strategies: 1) standard of care (SOC) referral to local clinics after delivery for separate standard ART services for women and pediatric care for infants, and 2) the MCH-ART intervention (MCH-ART) of co-located maternal/pediatric care integrated in Maternal and Child Health (MCH) services throughout breastfeeding. Trial-derived inputs included: 12-month maternal retention in care and virologic suppression (SOC: 49%, MCH-ART: 67%), breastfeeding duration (SOC: 6 months, MCH-ART: 8 months), and postpartum healthcare costs for mother-infant pairs (SOC: $50, MCH-ART: $69). Outcomes included pediatric HIV infections, maternal and infant life expectancy (LE), lifetime HIV-related per-person costs, and incremental cost-effectiveness ratios (ICERs; ICER <US$903/YLS considered "cost-effective").ResultsCompared to SOC, MCH-ART increased maternal LE (SOC: 25.26 years, MCH-ART: 26.20 years) and lifetime costs (SOC: $9,912, MCH-ART: $10,207; discounted). Projected pediatric outcomes for all HIV-exposed children were similar between arms, although undiscounted LE for HIV-infected children was shorter in SOC (SOC: 23.13 years, MCH-ART: 23.40 years). Combining discounted maternal and pediatric outcomes, the ICER was $599/YLS.ConclusionCo-located maternal HIV and pediatric care, integrated in MCH services throughout breastfeeding, is a cost-effective strategy to improve maternal and pediatric outcomes and should be implemented in South Africa.

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The value of confirmatory testing in early infant HIV diagnosis programmes in South Africa: A cost-effectiveness analysis.

Publications

The value of confirmatory testing in early infant HIV diagnosis programmes in South Africa: A cost-effectiveness analysis.

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