Study setting

This trial-based cost and cost-effectiveness analysis was nested in the LIFE study (NCT04032522), a pragmatic cluster-randomized trial which took place at 28 primary healthcare facilities in the Sofala and Manica provinces of Mozambique and the Mbeya and Songwe regions of Tanzania (7 sites per country per arm). The LIFE study enrolled 6,602 infants born to women living with HIV from October 2019 to September 2021: 3,294 in VEID sites and 3,308 in SoC sites. Among 125 infants diagnosed with HIV until 12 weeks of age, the study demonstrated a clinically relevant but not significant reduction in mortality up to 6 months of age with VEID. A total of 65 infants (52.0%) were diagnosed with HIV at birth. Vertical transmission was 1.89% (95% confidence interval [CI] [1.58, 2.25]) overall with 86.4% of infants (108) from Mozambique and 13.6% (17) from Tanzania [15].

Ethical considerations

Ethical approvals for the LIFE study were obtained from the Comité Institucional de Bioética para a Saúde of the Instituto Nacional de Saúde and Comité Nacional de Bioética em Saúde (Ref No. 509/CNBS/20) in Mozambique, the Mbeya Medical Research and Ethics Committee (Ref No. SZEC-2439/R.E/V. 1/90) and the Medical Research Coordinating Committee of the National Institute for Medical Research (Ref No. NIMR/HQ/R.8a/Vol. IX/3071) in Tanzania, and the Ethics Committee of the Ludwig Maximilians University Hospital (Ref No. 19–441) in Germany. All study participants provided written informed consent for themselves and their infants.

Testing and treatment procedures

Half of the sites implemented PoC EID within 72 hours of birth and at 4–8 weeks of age (VEID) and the other half at 4–8 weeks of age only (SoC) (Fig 1). Infants with negative or unknown HIV status at birth started post-natal prophylaxis and received PoC EID at follow-up visits at 4–8 and 12 weeks of age (plus 4-week window period). HIV–positive results were confirmed by a second PoC EID test or, if a valid result could not be obtained on site, HIV-DNA performed at a central laboratory from dried blood spots. Infants diagnosed with HIV were immediately started on ART. Dried blood spots were collected for all infants at SoC sites at birth for retrospective analysis of HIV status at birth and in the case of death or loss to follow-up with unknown HIV status.

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Fig 1. Testing and treatment algorithms.

HIV-exposed infants received their first HIV test in the maternity ward (VEID) or the pediatric clinic (SoC), where follow-up visits were also performed. (A) In Mozambique, each clinic had one mPIMA analyzer. (B) In Tanzania, each health facility had one Xpert analyzer. Infants with HIV–positive test results were immediately initiated on ART. Infants with HIV–negative test results were initiated on post-natal prophylaxis according to country guidelines: AZT + NVP for all infants in Mozambique and high-risk infants in Tanzania and NVP only for low-risk infants in Tanzania.VEID, very early infant (HIV) diagnosis; SoC = standard of care; PoC EID, point-of-care early infant (HIV) diagnosis; AZT, zidovudine; 3TC, lamivudine; NVP, nevirapine; ABC, abacavir. Created in BioRender. Hoelscher, M. (2025) https://BioRender.com/t4btr5b.

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Following routine guidelines, all infants exposed to HIV in Mozambique were given enhanced post-natal prophylaxis with zidovudine (AZT) syrup for 6 weeks plus nevirapine (NVP) syrup for 12 weeks [17]. In Tanzania, only high-risk infants (i.e., mother newly diagnosed with HIV, not on ART or on ART for less than four weeks, or with high viral load in the last four weeks), were given enhanced post-natal prophylaxis. Standard post-natal prophylaxis with NVP syrup for 6 weeks was given to low-risk infants [18]. ART for infants with HIV aged 0–4 weeks and at least 2 kg consisted of AZT, lamivudine (3TC), and NVP syrups. At 4 weeks of age and at least 3 kg, infants were given abacavir (ABC)/3TC dispersible tablets and lopinavir/ritonavir (LPV/r) granules. Nurses were trained in sample collection and use of the PoC analyzers, performed all PoC testing and pre- and post-test counseling, and initiated ART with physician support.

Testing platforms

The Abbott mPIMA HIV-1/2 Detect and Cepheid Xpert HIV-1 Qual were used for PoC EID testing in Mozambique and Tanzania, respectively, reflecting preexisting local HIV program preferences. The mPIMA analyzer is also approved for HIV viral load and can be procured with an external battery to bridge power outages. The Xpert analyzer can run HIV viral load, tuberculosis diagnosis, and other assays (though equipment sharing across programs is not common practice in the study setting). In Tanzania, two variations of the Xpert analyzer were available: Xpert II with the capacity to run two and Xpert IV four assays concurrently. In general, Xpert IV analyzers were placed at higher volume sites. In Tanzania, PoC analyzers were located in the pediatric outpatient clinic or health facility laboratory. In Mozambique, PoC analyzers were placed at the pediatric outpatient clinic, and an additional analyzer was placed at the maternity ward in VEID sites. Both analyzers have comparable diagnostic performance and run-time for EID [19,20]. Therefore, we expect that the choice of platform did not affect linkage to ART or other health outcomes.

Costing approach

We conducted a micro-costing study from the health system perspective. We estimated implementation and operations costs as they occurred in the LIFE study, including fixed costs (equipment purchase, installation, and maintenance; utilities; communication; training; and facility upgrades) and variable costs (consumables, labor, and ART) for VEID and SoC approaches. Direct client and societal costs were excluded from this analysis, as the study was designed to focus on direct budgetary and resource allocation impact on the healthcare provider. The time horizon for individual-level cost and effectiveness outcomes corresponded to the 12-week follow-up period, during which clinical pathways and resource use differed between arms. Beyond this period, costs and clinical management were assumed to be equivalent in both arms. Infants lost to follow-up after birth in the SoC arm incurred no intervention-related resource use and were therefore treated as structural zeros with respect to costs.

We first identified resources used for VEID from study documents, local HIV testing and care guidelines, and communication with implementing partners. To measure quantities of resources consumed, we used data from the LIFE study and usage data from the PoC analyzers. Consumables, labor, and ART were collected using a bottom-up approach. Time required for nurses to conduct PoC EID tests and perform HIV-related counselling was collected as anonymous self-reported average active work time once they had logged sufficient experience with PoC testing (>50 tests/individual). Fixed costs were allocated to EID testing according to observed testing volume; consumables, labor, and ART costs were allocated directly per test or per infant. Facility upgrades included the purchase of cabinets to store reagents and the installation of air conditioning units in some sites. Fixed costs were shared with routine services, including HIV viral load monitoring. Shared resources (e.g., analyzers, utilities, and communication) were allocated proportionally based on observed PoC EID testing volume relative to total analyzer use.

Prices for resources were collected from Ministry of Health budgets and expenditure reports, purchase tenders, manufacturer contracts, and government salary scales. Test cartridges were procured at a flat rate inclusive of shipping, customs clearance, distribution, and administration costs. Capital costs were discounted at 3% per year and amortized using equivalent annual cost—PoC platform costs over a 5-year life span according to manufacturer specifications and other capital costs over 10 years. Cost data collected for 2020 and 2021 were converted to nominal 2020 United States dollars (US$) using World Bank Global Economic Monitor annual mean exchange rates [21]. At the time of the study, these were 66.8 Mozambique Metical and 2304.4 Tanzanian Shillings per 1 US$ for 2020 and 64.4 Mozambique Metical per 1 US$ for 2021. No costs paid in Tanzanian Shillings were collected for 2021. Further costing details are provided in S1 Text.

Outcomes

We assessed the proportion of infants with HIV initiating ART within 1 week of life, defined as trial-documented initiation of ART on or before day seven after birth, as the primary effectiveness outcome. We also assessed the proportion of infants exposed to HIV receiving an EID test within eight weeks of life as a secondary effectiveness outcome. EID testing was documented in study visit records and confirmed with PoC analyzer logs. Incremental costs, incremental effectiveness, and incremental cost-effectiveness ratios (ICERs) per additional infant initiating ART within 1 week and per additional infant receiving a PoC EID test within 8 weeks were estimated relative to the SoC. In the absence of robust data quantifying the incremental survival benefit associated with starting ART in the first week relative to starting at 4–8 weeks of life, we conducted a break-even analysis to derive the minimum life-years that would need to be gained per additional infant initiating ART within one week of life for our intervention to be considered cost-effective given standard cost-effectiveness thresholds.

Statistical analysis

Frequentist methods were used for descriptive summaries and unadjusted comparisons between study arms. Descriptive cost per test and per infant were reported as testing volume-weighted mean and bootstrapped 95% CI per country and study arm to reflect typical costs across sites. To show the influence of testing volume on cost per test, we additionally presented unweighted medians by low-, medium-, and high-volume sites. Summary measures for effectiveness outcomes were reported as proportions for the probability of EID testing and ART initiation and median and range for age at first EID test and ART initiation.

Incremental costs and incremental effectiveness were estimated using multivariate Bayesian hierarchical models to account for skewed distribution of cost data and clustering at the health facility level, with results reported as posterior mean and 95% credible interval (CrI). Costs were modeled on the natural scale using a hurdle Gamma specification to accommodate observed zeros arising from infants who did not receive EID testing due to loss to follow-up, while effectiveness outcomes were modeled as Bernoulli processes. Models were fit separately for 1-week ART and 8-week PoC EID effectiveness outcomes with country- and site-level random effects to capture intra-cluster correlation and differences in costs, PoC testing platforms, prophylaxis protocols, and transmission rates. For the 1-week ART model, site-level random effects were not included due to sparse outcome variation within clusters, which precluded reliable estimation of additional variance components. The country was included as a fixed effect to account for the systematic differences in context. Informative priors were specified for study arm effects to reflect expected differences between VEID and SoC arms. Prior sensitivity analyses using weakly informative priors were conducted to assess the robustness of model estimates to prior specification. Model convergence was confirmed (all R� ≈ 1), and posterior predictive checks indicated good agreement between observed and replicated data. Full model specification, priors, and diagnostics are provided in S1 Text.

ICER point estimates were calculated as the ratio of mean incremental cost to mean incremental effect from the posterior distributions. To reflect uncertainty around these estimates, we used posterior draws of incremental cost and incremental effect jointly sampled from the Bayesian hierarchical models in probabilistic sensitivity analyses. Uncertainty was visualized in cost-effectiveness planes showing additional costs versus additional benefit for VEID over SoC. The probability of each PoC EID approach being cost-effective at a range of WTP thresholds is shown in cost-effectiveness acceptability curves. To contextualize results, we referenced empirically derived country-level cost-effectiveness thresholds from Pichon-Riviere and colleagues [22], which are based on health expenditure per capita and life expectancy growth and expressed as cost per life-year gained. These were $189 per life-year in Mozambique and $316 per life-year in Tanzania (2020 US$). For comparability with previous studies, we also considered GDP per capita as a willingness-to-pay (WTP) threshold ($462 in Mozambique and $1,117 in Tanzania per life-year gained) [21]. As ICERs in this analysis are expressed in cost per additional infant initiating ART within 1 week of life rather than per life-year gained, they cannot be directly compared to these thresholds. Rather than model long-term health outcomes directly, we conducted a break-even analysis to derive the minimum life-years that would need to be gained per additional infant initiating ART within one week of life for VEID to meet these thresholds, calculated as the posterior draw of incremental cost divided by the WTP threshold. Results are reported as median and 95% CrI.

Cost data was compiled in Microsoft Excel (Microsoft Corp.). Statistical analysis was performed using R version 4.2.3 (R Foundation for Statistical Computing, Vienna, Austria). Analyses followed a pre-specified health economic analysis plan. This study is reported as per the Consolidated Health Economic Evaluation Reporting Standards 2022 (CHEERS 2022) Statement [23] (S1 Checklist). Figures were created with R and BioRender.com.

Sensitivity analyses

Deterministic sensitivity analyses were utilized to explore the impact of selected drivers of cost per test not explicitly parameterized in the Bayesian hierarchical models. We chose ranges reflective of plausible uncertainty and policy-relevant scenarios. Consumable prices were varied by ±50% to account for uncertainty in procurement and distribution costs, testing volume from −50% to 200% of observed levels to reflect variability across sites and potential scale-up, analyzer life span from 4 to 15 years for a conservative lower bound and assumptions that PoC platforms can last longer with maintenance, and discount rate from 0% to 6% in line with standard guidance [24]. This analysis was designed to decompose cost-input uncertainty and identify key drivers of unit costs across policy-relevant scenarios, and is distinct from the probabilistic sensitivity analysis, which addresses decision uncertainty.

We additionally varied the intrauterine transmission rate across a wide range of values within a probabilistic sensitivity analysis framework to assess how cost-effectiveness would vary across epidemiological contexts and to identify threshold levels of transmission at which VEID would meet common cost-effectiveness benchmarks. Additional probabilistic uncertainty around ICERs was captured in the main analysis and visualized in cost-effectiveness planes and acceptability curves. Here, we focused on scenario-driven variation.

Age of early infant HIV diagnostic testing and ART initiation

In VEID sites, 100% of infants exposed to HIV had a PoC EID test by the recommended 8 weeks of age (median 1 day, interquartile range [IQR]: 0–1 days), compared with 84.4% in SoC sites (median 4.7 weeks, IQR: 4.4–6.4) (Fig 2A and Fig AA in S1 Text). Proportions of infants receiving PoC EID testing by eight weeks in SoC sites differed substantially by country with 91% in Mozambique and 75% in Tanzania. Repeat testing due to errors or confirmatory testing was performed for 9.5% versus 3.7% in Mozambique and 9.9% versus 8.7% in Tanzania of infants for VEID and SoC approaches, respectively.

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Fig 2. Time from birth to PoC EID testing and treatment initiation.

(A) First EID test among all HIV-exposed infants; proportion receiving an EID test indicated in vertical axis labels. (B) ART initiation among infants diagnosed with HIV up to 16 weeks; proportion initiating ART at all indicated in vertical axis labels. Box plots show median (center line), 25% and 75% (box limits), and 5% and 95% (whiskers); violin plots show data distribution. VEID, very early infant (HIV) diagnosis; SoC = standard of care; PoC EID, point-of-care early infant (HIV) diagnosis; ART, antiretroviral treatment. Created in BioRender. Hoelscher, M. (2025) https://BioRender.com/u260ruo.

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In VEID sites, 98.6% of infants diagnosed with HIV started ART compared to 89.3% in SoC sites, and among infants with an HIV–positive result available at birth (VEID sites), 89.5% started ART within the first week of life. The median age at ART initiation was 0.9 (range: 0–14) weeks in VEID sites and 4.7 (range: 4–16) weeks in SoC sites (Fig 2B and Fig AB in S1 Text). Reasons for not starting ART were death or loss to follow-up. Reasons for delayed treatment initiation at birth were not meeting the minimum weight requirement for neonatal antiretroviral dosing and a delay in confirmatory HIV testing.

Costs of very early infant diagnosis versus standard-of-care

Cost per test was $39.81 (95% CI [$37.44, $43.70]) for the VEID approach and $41.97 (95% CI [$39.04, $46.58]) for the SoC approach using mPIMA in Mozambique. Using Xpert in Tanzania, these costs were $33.91 (95% CI [$30.85, $40.92]) for VEID and $39.90 (95% CI [$34.30, $49.75]) for SoC. Lower cost per test for the VEID approach reflects higher testing volumes, since infants were tested twice by design and fixed costs were allocated across more tests. Cost per infant exposed to HIV, which incorporates PoC EID testing and, if appropriate, earlier ART initiation was $90.13 (95% CI [$88.76, $91.47]) for VEID versus $39.70 (95% CI [$39.00, $40.42]) for SoC in Mozambique and $67.81 (95% CI [$66.26, $69.43]) for VEID versus $35.92 (95% CI [$34.67, $37.20]) for SoC in Tanzania. Cost inputs used to derive unit costs per test and per infant are listed in Table 1.

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Table 1. Costs of inputs. Costs expressed in 2020 US$ by category for each country/PoC testing platform.

https://doi.org/10.1371/journal.pmed.1005069.t001

Consumables, primarily the test cartridge, accounted for 63% in Mozambique and 58% in Tanzania of the cost per test (Fig 3, Fig B and Table A in S1 Text). Equipment and overhead costs, by contrast, varied substantially by testing volume. We categorized health facilities into high (>12 tests per week), medium (5–12 tests per week) and low (<5 tests per week) volume for ease of comparison (S1 Text). On average in Mozambique, four (29%) sites ran over 15 tests weekly and two (14%) ran less than five tests weekly. In Tanzania, only one (7%) site ran over 15 tests weekly and six (43%) ran less than five tests weekly. Cost per test varied by 33% in Mozambique and 63% in Tanzania between high and low volume sites, with the greater variability in Tanzania driven by a larger number of low volume sites compared to Mozambique. Labor and overhead costs were small in comparison to consumable and equipment costs in both countries.

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Fig 3. PoC EID test cost components.

(A) Cost estimates expressed in 2020 US$. (B) Proportion of total cost per test. Sites are categorized as high (>12 tests per week), medium (5–12 tests per week), and low (<5 tests per week) testing volume. Equipment includes amortized costs of initial purchase, installation, and yearly maintenance of PoC analyzers. Overhead includes apportioned costs of electricity, communications, and facility upgrades. Overhead and labor costs were < $3 per test (<6% of cost per test) across all sites.

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Cost-effectiveness of very early infant HIV diagnosis

VEID was associated with higher costs and improved effectiveness outcomes in both countries (Fig 4, Tables B-C in S1 Text). In Mozambique, VEID increased the proportion of infants initiating ART within one week of life by 90.0 (95% CrI [67.5, 98.5]) percentage points at an incremental cost of $2,632 (95% CrI [$2,249, $3,062]) per infant with HIV. In Tanzania, the incremental cost was higher at $6,263 (95% CrI [$5,394, $7,243]), with a 59.9 (95% CrI [20.9, 89.5]) percentage point increase in the proportion initiating ART within one week. The corresponding ICER with respect to additional infants initiating ART within one week of life was $2,924 in Mozambique and $10,458 in Tanzania.

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Fig 4. Cost-effectiveness of VEID with respect to PoC EID testing and early ART.

Cost-effectiveness planes presenting the incremental costs and (A and B) early ART benefit (% of eligible infants with HIV initiated on ART within 1 week of life; eligible infants include those meeting clinical criteria for treatment, e.g., weight) or 8-week EID benefit (%) for VEID (E and F). Points represent estimates of costs and health benefit for VEID relative to SoC at the origin. A random sample of 500 points is plotted. All estimates indicate that VEID is more expensive and results in increased health benefit (upper right quadrant). (C and D; G and H) Cost-effectiveness acceptability curves for each outcome in A-B and E-F, respectively, showing cumulative probabilities of each testing strategy being cost-effective at a particular willingness to pay value. Costs are presented as 2020 US$. PoC EID, point-of-care early infant (HIV) diagnosis; ART, antiretroviral treatment; SoC = standard of care; VEID, very early infant (HIV) diagnosis.

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Based on the break-even analysis, VEID would need to achieve 15.24 (95% CrI [12.63, 21.37]) life-years gained per additional infant initiating ART within 1 week of life in Mozambique and 32.17 (95% CrI [21.15, 94.84]) in Tanzania to meet empirically derived cost-effectiveness thresholds [22] (Fig 5). At WTP thresholds based on 1x GDP per capita, the corresponding required life-years gained were 6.24 (95% CrI [5.17, 8.74]) in Mozambique and 9.10 (95% CrI [5.98, 26.83]) in Tanzania.

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Fig 5. Required life-years per early ART initiation for cost-effectiveness.

Shaded ribbons for Mozambique and Tanzania indicate 95% credible interval (CrI) across posterior draws from the Bayesian hierarchical model for 1-week ART initiation. Empirically derived cost-effectiveness thresholds, based on health expenditure and life expectancy growth [21] and expressed in 2020 US$, were $189 in Mozambique and $316 in Tanzania. 2020 gross domestic product per capita-based thresholds were $462 in Mozambique and $1,117 in Tanzania. Higher required life-years reflect scenarios in which greater health gains per infant would be needed to approach the indicated thresholds.

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Implementation of VEID also increased uptake of EID. In Mozambique, VEID increased the proportion of infants receiving an EID test within eight weeks of life by 8.0 (95% CrI [5.4, 11.2]) percentage points at an incremental cost of $50.72 (95% CrI [$43.72, $58.65]) per infant exposed to HIV. In Tanzania, the corresponding increase was 20.9 (95% CrI [14.9, 28.0]) percentage points in the proportion of infants receiving an EID test within eight weeks of life at an incremental cost of $28.52 (95% CrI [$24.39, $33.19]) per infant exposed to HIV. The ICER with respect to additional infants receiving an EID test within eight weeks of life was $635.47 and $136.19 in Mozambique and Tanzania, respectively.

Sensitivity analysis

Cost per test was most sensitive to relative changes in the price of consumables, followed by testing volume and PoC analyzer life span (Fig 6 and Fig C in S1 Text). We observed moderate variability in baseline cost across health facilities resulting from different testing volumes and 5% probability of zero cost across all sites (i.e., infants not receiving testing mostly in SoC sites due to loss to follow-up after birth). Site-level variation was modest with an intra-cluster correlation of 0.033 (95% CrI [0.018, 0.059]) for cost per infant and 0.140 (95% CrI [0.066, 0.258]) for PoC EID within eight weeks. Sites with higher baseline costs tended to experience smaller increases in cost per additional test as testing volumes increased (posterior correlation ρ = −0.25), consistent with economies of scale. Due to low number of infants diagnosed with HIV in Tanzania, uncertainty in effectiveness outcomes was high; combined with uncertainty in costs, this resulted in substantial uncertainty in the ICER with respect to ART initiation in the first week of life in Tanzania.

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Fig 6. Deterministic one-way sensitivity analysis showing influence of key assumptions on cost per PoC EID test.

Costs expressed in 2020 US$. Per test cost difference is shown on the x-axis and parameters with ranges are shown on the y-axis. High and low colors indicate the direction in which the parameter varies. This analysis addresses cost-input uncertainty rather than decision uncertainty; see Figure 4 for probabilistic sensitivity analysis of incremental cost-effectiveness.

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Intrauterine transmission rates observed in the LIFE study were 1.01% (95% CrI [0.65, 1.51]) in SoC sites and 1.48% (95% CrI [1.01, 2.06]) in VEID sites in Mozambique and 0.43% (95% CrI [0.16, 0.85]) in SoC sites and 0.50% (95% CrI [0.19, 0.94]) in VEID sites in Tanzania. The ICER with respect to additional infants initiating ART within one week of life was sensitive to intrauterine transmission rate, ranging from $2,394 to $4,009 in Mozambique and from $5,993 to $27,424 in Tanzania between the 5th and 95th percentiles of estimated intrauterine transmission. In Mozambique, intrauterine transmission would need to exceed 34% to meet the cost-effectiveness threshold from [22] or 14% to meet the GDP-based threshold (Fig 7). In Tanzania, the corresponding intrauterine transmission rates were 20% and 5.8%, respectively, indicating that VEID becomes cost-effective only above specific thresholds of early vertical transmission risk. These thresholds are based on cost per additional infant initiating ART within 1 week of life and do not directly incorporate downstream life-years gained, which are explored separately above.

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Fig 7. Sensitivity analysis of the incremental cost effectiveness ratio (ICER) per infant with HIV on ART within 1 week across a range of intrauterine transmission rates, based on posterior estimates from the Bayesian hierarchical model.

Lines show the posterior mean ICER, with shaded areas representing the 95% credible intervals. Dashed horizontal lines indicate reference willingness to pay (WTP) thresholds: empirically derived cost-effectiveness thresholds based on health expenditure and life expectancy growth from [21], expressed in 2020 US$ ($189 for Mozambique and $316 for Tanzania) and gross domestic product per capita in 2020 ($462 for Mozambique and $1,117 for Tanzania).

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