Gaps in HIV testing for children of mothers with known HIV positive status: Results from Population-based HIV Impact Assessments (PHIA) in Sub-Saharan Africa (2015-2019)

An analysis of 13 Population-based HIV Impact Assessments in Sub-Saharan Africa (2015–2019) reveals that over 40% of children born to mothers aware of their HIV-positive status had never been tested, highlighting critical gaps in pediatric diagnosis and treatment linkage despite high confirmation rates among known cases.

The Gist

Imagine a massive safety net designed to catch children who might have inherited HIV from their mothers. In an ideal world, this net would be tight, with no holes, ensuring every child is caught, tested, and given medicine immediately.

This paper is like a report card on how well that safety net is actually working in 13 countries across Sub-Saharan Africa. The researchers looked at data from 2015 to 2019 to see where the holes are.

Here is the story of their findings, broken down into simple concepts:

1. The "Known" Problem and the "Hidden" Gap

The study focused on a specific group: children whose mothers already knew they had HIV. You would think, "If the mom knows she has HIV, she would definitely get her kids tested, right?"

The Reality: It turns out, about 4 out of every 10 children in this group had never been tested for HIV.

• The Analogy: Imagine a lighthouse (the mother) that knows there are dangerous rocks (HIV) nearby. You'd expect the lighthouse keeper to warn every ship (child) passing by. But in this case, the lighthouse keeper was shining the light, yet 40% of the ships were sailing in the dark, never checking if they had hit a rock.

2. The "Newly Found" Infections

The researchers went into these communities and tested the children themselves. They found that even among children who had never been tested before, a small but significant number were actually living with HIV.

• The Stat: About 3% of the untested children were found to have HIV.
• The Analogy: It's like finding a few hidden weeds in a garden that the gardener thought was clear. Even though the gardener (the mother) knew the soil was tricky, she didn't check every single plant, and some weeds were growing unnoticed.

3. The "Medicine" Gap

For the children who did know they had HIV, the next step is to give them life-saving medicine (ART).

• The Problem: About 9% of the children who knew they were HIV-positive were not taking their medicine.
• The Analogy: Imagine you have a key to a treasure chest (the medicine) that keeps you alive, but you left it in your pocket and forgot to use it. These children had the key, but for various reasons, they weren't turning the lock.

4. Why Are the Holes in the Net?

The study asked, "Why aren't these kids getting tested?" They found several reasons, which act like barriers blocking the path to the doctor:

• Distance: Living in rural areas (far away from the clinic) made it harder to go.
• Silence: If the mother was afraid to tell others she had HIV (due to shame or stigma), she wouldn't ask for her child to be tested.
• Healthcare Visits: If the family hadn't visited a doctor in the last year, the child didn't get tested.
• School: Interestingly, children who were not in school were less likely to be tested. Schools often act as a bridge to health services.

5. The "False" Reports

The study also found some confusing mix-ups:

• Some parents said, "My child is HIV positive," but when tested, the child was negative. (Maybe the parent was mistaken, or the child had been treated so well the virus was undetectable).
• Some parents said, "My child is HIV negative," but the child actually had HIV. (This often happened because the parent didn't know the child's true status or was afraid to admit it).

The Big Takeaway

The authors conclude that while we have made progress, the safety net still has big holes.

• The Goal: We need to fix the "Index Testing" strategy. This is a fancy term for "If Mom has it, check the kids."
• The Call to Action: We need to make it easier for mothers to bring their kids to the clinic, reduce the shame around HIV so mothers speak up, and ensure that once a child is diagnosed, they immediately get their medicine.

In short: We know where the danger is (the mothers), but we are still missing too many children who need help. The study is a wake-up call to tighten the net so no child falls through the cracks.

Technical Summary

1. Problem Statement

Despite global efforts to prevent vertical transmission of HIV, a significant proportion of children living with HIV (CLHIV) in sub-Saharan Africa remain undiagnosed and untreated.

• The Gap: While Prevention of Vertical Transmission (PVT) programs exist, testing of HIV-exposed children is suboptimal. Many children are diagnosed late, increasing morbidity and mortality risks.
• Index Testing Potential: Children of adults living with HIV (WLHIV) have a higher likelihood of being HIV-positive (up to 65% of undiagnosed children have an HIV-positive family member). Family-based "index testing" is a proven strategy to find these missed cases, yet coverage remains suboptimal (14–71%).
• Objective: The study aimed to quantify the gap in HIV diagnosis among children of WLHIV who were already aware of their own positive status, and to identify factors associated with children never having been tested.

2. Methodology

Study Design & Data Source:

• Data: Pooled, cross-sectional data from 13 Population-based HIV Impact Assessments (PHIA) conducted between 2015 and 2019.
• Countries: Cameroon, Côte d'Ivoire, Eswatini, Ethiopia, Kenya, Lesotho, Malawi, Namibia, Rwanda, Tanzania, Uganda, Zambia, and Zimbabwe.
• Target Population: Children <15 years old linked to women living with HIV (WLHIV) who were alive, >15 years old, and aware of their HIV-positive status prior to the survey.

Data Collection & Biomarkers:

• Household Surveys: Standard questionnaires collected data on HIV testing history, status, and ART use from parents/guardians.
• Biomarker Testing:
  • Children >18 months: Rapid HIV testing followed by confirmatory Geenius™ assay if positive.
  • Children ≤18 months: Determine™ HIV-1/2 screening followed by HIV-1 DNA PCR (virologic testing).
  • ART Detection: Dry Blood Spots (DBS) were tested for antiretroviral (ARV) presence using liquid chromatography-tandem mass spectrometry (LC-MS/MS).
• Classification:
  • Known HIV Positive: Child reported as positive AND had detectable ARVs.
  • Newly Diagnosed: Child tested positive during the survey but had no detectable ARVs (indicating they were previously undiagnosed or off treatment).

Statistical Analysis:

• Weighting: Survey weights were pooled across countries to account for complex sampling designs and non-response, allowing for population-level estimates.
• Modeling: Logistic regression (using survey-weighted generalized linear models) was used to identify factors associated with children having "unknown" HIV status (never tested).
• Software: R version 4.2.

3. Key Contributions

• Large-Scale Pooled Analysis: This is one of the first studies to pool data from 13 national surveys to provide a regional estimate of testing gaps specifically for children of known WLHIV, a high-risk group often missed by standard PVT protocols.
• Biomarker Validation: Unlike many studies relying solely on self-report, this study utilized biomarker data (PCR and ARV detection) to objectively classify children as "newly diagnosed" vs. "known positive," revealing discrepancies between caregiver reports and biological reality.
• Identification of Systemic Gaps: The study highlights that even when mothers are on treatment and aware of their status, a significant portion of their children remain untested and untreated.

4. Key Results

Testing Gaps:

• Untested Children: Of 6,173 children linked to WLHIV who were aware of their status, 43.5% (n=2,371) had never been tested for HIV.
• New Diagnoses: Among children tested during the survey:
  • 2.9% of those with reported "unknown" status tested positive (newly diagnosed).
  • 0.9% of those reported as "HIV negative" tested positive (newly diagnosed).
  • Overall new test positivity was 1.7%.

Treatment Cascade (Among HIV-Positive Children):

• Of the 387 HIV-positive children identified:
  • 74.6% were known to be positive prior to the survey.
  • 92.8% of those known positive were on ART.
  • 43.9% were virally suppressed.
  • 9.0% of children known to be HIV-positive were not on ART at the time of the survey.
• Estimated Burden: The study extrapolates that approximately 55,985 children of WLHIV in these countries were either undiagnosed or HIV-positive but not on ART.

Factors Associated with Lack of Testing:
Children were significantly more likely to have never been tested if:

• Geography: Living in rural areas.
• Healthcare Access: The household had not visited a healthcare worker in the last 12 months.
• Parental Status: The mother had not disclosed her HIV status, was not on ART, or had a high viral load.
• Child Factors: The child was not enrolled in school.
• Illness: Absence of illness in parents (counter-intuitively, lack of parental illness reduced the likelihood of testing, suggesting a "sick-child" bias in testing triggers).

Discrepancies in Reporting:

• False Negatives: 5.5% of children reported as HIV-positive by guardians tested negative during the survey (potentially due to early treatment suppressing viral load to undetectable levels or misreporting).
• False Negatives (Undiagnosed): 0.9% of children reported as negative tested positive (likely due to non-disclosure or seroconversion during breastfeeding).

5. Significance and Implications

• Re-evaluating Index Testing: The findings indicate that current index testing strategies are failing to reach nearly half of the children of WLHIV. The "sick-child" bias (testing only when a child is ill) is a major barrier; testing must be proactive regardless of the child's health status.
• School-Based Interventions: Since school enrollment was a strong predictor of testing, integrating HIV testing into school health programs could be a high-yield strategy for older children (5–14 years).
• Treatment Linkage: The fact that 9% of known positive children were not on ART highlights a breakdown in the treatment cascade. Strengthening retention and adherence support is critical.
• Policy Shift: The study calls for a shift from passive, facility-based testing to active, community-based family testing, particularly for children who are asymptomatic and not currently engaging with health services.
• Data Quality: The discrepancies between self-reported status and biomarker results underscore the need for routine biomarker verification in program monitoring to accurately assess the epidemic's true size.

Conclusion:
The study concludes that despite high maternal awareness and treatment rates, a massive gap remains in pediatric HIV case identification. Renewed efforts are required to enhance testing coverage for children of WLHIV and ensure immediate linkage to treatment for those diagnosed.