Gabon’s PMTCT Cuts Baby HIV Risk Sharply, but Early Diagnosis Lags

A large observational study from Gabon has delivered some of the clearest numbers yet on how well the country is doing at stopping HIV from passing from mothers to their babies, and the results tell a story of two very different realities. On one hand, the prevention machinery is working: nearly 92 percent of HIV-positive mothers in the study received antiretroviral therapy or prophylaxis during pregnancy or breastfeeding, and their infants rarely became infected. On the other hand, the system that should catch infections early and keep children in care is faltering badly, with only about one in eight HIV-exposed infants completing the full schedule of early diagnostic testing.

The research, published in BMC Public Health by a team based at the Centre Interdisciplinaire de Recherches Médicales de Franceville and collaborating institutions, followed 713 HIV-exposed children and their biological mothers between August 2021 and January 2024. Each mother-child pair was enrolled once, and the investigators combined structured questionnaire data with laboratory results from HIV DNA PCR testing, the molecular technique that detects the virus’s genetic material in an infant’s blood rather than relying on antibodies, which can be inherited passively from the mother and confuse diagnosis in the first months of life.

The headline finding concerns the power of prevention of mother-to-child transmission, known universally as PMTCT. Among the 655 children whose mothers received antiretroviral treatment or prophylaxis during pregnancy or breastfeeding, only 15, or 2.3 percent, tested HIV-positive. Among the 58 children whose mothers received no PMTCT intervention at all, 22, or 37.9 percent, were infected. In other words, the infection rate was more than sixteen times higher when mothers went without prevention services.

When the team ran bias-reduced multivariable logistic regression, a statistical approach designed to produce more stable estimates than conventional models when sample sizes are limited or predictors are numerous, maternal receipt of PMTCT remained strongly and independently associated with lower odds of infant infection. The adjusted odds ratio was 0.04, with a 95 percent confidence interval of 0.02 to 0.08 and a p-value below 0.001. Technically, that means a baby whose mother received PMTCT had roughly a 96 percent reduction in the odds of HIV infection compared with a baby whose mother did not, after accounting for other measured factors.

Yet the study also documents stubborn residual transmission. Even with prevention coverage above 90 percent, 5.2 percent of all HIV-exposed children in the cohort, 37 of 713, were HIV-positive. Some of these infections occur despite intervention, reflecting well-known failure modes in vertical transmission: mothers who start antiretroviral therapy late in pregnancy, viral suppression that is incomplete at delivery, adherence lapses during breastfeeding, or infants who acquire the virus through breast milk even when maternal prophylaxis was in place. The Gabonese data cannot disentangle these mechanisms individually, but the persistence of infection at this rate signals that prevention alone, however effective, will not eliminate pediatric HIV without parallel improvements in detection and follow-up.

That is where the second half of the study becomes sobering. Early infant diagnosis, or EID, is the internationally recommended pathway of virological testing for babies born to HIV-positive mothers, typically involving HIV DNA PCR at birth or within the first weeks of life, with repeat testing at defined intervals and a final test after breastfeeding ends. World Health Organization guidance calls for infants to move through this schedule so that infected babies can start antiretroviral therapy quickly, because untreated pediatric HIV progresses rapidly and mortality in the first two years of life is high. In the Gabonese cohort, the mean number of PCR tests per child was 1.6, with a standard deviation of 0.9, and only 12.5 percent of children, 89 of 713, completed the full EID schedule.

The implications of incomplete EID are serious. A single negative PCR test early in infancy does not exclude infection acquired later through breastfeeding, which is why guidelines insist on repeated testing. Children who receive one test and then disappear from the system may harbor undetected infection for months, arriving at care only when symptomatic. The study’s finding that specialized pediatric HIV care was documented for 41.4 percent of children, 295 of 713, suggests that more than half of HIV-exposed infants were not being tracked through dedicated services at all, a gap that undermines both diagnosis and treatment initiation.

Perhaps the most counterintuitive result is that follow-up in specialized pediatric HIV care was not independently associated with either infant HIV infection or EID completion. The adjusted odds ratio for infection among children in specialized care was 1.00, with a 95 percent confidence interval of 0.46 to 2.13 and a p-value of 0.995, effectively no association. For EID completion, the odds ratio was 1.16, with an extraordinarily wide confidence interval of 0.01 to 222.85 and a p-value of 0.943, a result so imprecise that it cannot support any conclusion about direction. The authors interpret this as evidence that enrollment in specialized services, by itself, is not translating into better outcomes, possibly because children enter these services late, irregularly, or only after a diagnosis has already been made.

The study team, led by Berthe Amélie Iroungou of the Unité Mixte de Recherche CIRMF-Service de Santé Militaire in Libreville, argues that the findings should redirect attention toward the postnatal portion of the pediatric HIV cascade. Their recommendations include systematic tracking of HIV-exposed infants from birth, repeated virological testing at guideline-specified intervals, and expanded access to specialized pediatric HIV services. The work was supported by CIRMF without dedicated project funding, and the diagnostic capacity for HIV DNA PCR testing was strengthened through collaboration with DHAPP, MCDI, and IPHASA, organizations that facilitated laboratory access and supported evidence-based clinical decision-making.

For Gabon, the study provides a quantitative baseline for a problem that has been difficult to measure. Data on early infant diagnosis and postnatal follow-up of HIV-exposed children have been scarce in the country, and this cohort of 713 mother-child pairs represents one of the most detailed pictures available. The message embedded in the numbers is that Gabon has largely solved the first step of preventing mother-to-child transmission but has not yet built the bridge from prevention to sustained pediatric care. Closing that bridge, the authors conclude, is the priority if the country hopes to push its pediatric HIV infection rate from 5.2 percent toward the elimination targets that global health agencies have set for vertical transmission.

Subject of Research: PMTCT and early infant diagnosis among HIV-exposed infants in Gabon: associations with HIV infection and continuity of care

Article Title: PMTCT and early infant diagnosis among HIV-exposed infants in Gabon: associations with HIV infection and continuity of care

Article References: Iroungou, B. A., Dikoumba, A.-C., Longo-Pendy, N. M., Akombi, F. L., Boundenga, L., & Mangouka, G. L. (2026). PMTCT and early infant diagnosis among HIV-exposed infants in Gabon: associations with HIV infection and continuity of care. BMC Public Health. https://doi.org/10.1186/s12889-026-29660-8

Image Credits: AI Generated

DOI: 10.1186/s12889-026-29660-8

Keywords: HIV, PMTCT, early infant diagnosis, pediatric HIV, Gabon, sub-Saharan Africa, HIV DNA PCR, continuity of care, mother-to-child transmission, antiretroviral therapy, early, infant