Time-Trend,Regional and National Prevalence of Vertical Transmission of HIV-1 in Sub-Saharan Africa: A Systematic Review and Meta-Analysis

Abstract

Background

Despite substantial global progress in HIV prevention and treatment, mother-to-child transmission (MTCT) of HIV remains a major public health challenge in sub-Saharan Africa, which accounts for approximately 65% of the world’s 39.9 million people living with HIV. Vertical transmission rates vary substantially across regions and over time. We conducted a systematic review and meta-analysis to estimate the overall, temporal, regional, and country level prevalence of HIV MTCT in sub-Saharan Africa.

Methods

This research was conducted between June 2024 and May 2025, in accordance with PRISMA guidelines and a protocol registered in PROSPERO (CRD42025637989). We systematically searched six databases (MEDLINE, Embase, PubMed, ScienceDirect, Web of Science, and the Cochrane Library) for articles published in English or French. We included cross-sectional, cohort, and case-control studies involving HIV-positive pregnant women aged ≥18 years that reported MTCT prevalence. Two reviewers independently screened, extracted data, and assessed study quality (Joanna Briggs Institute and Newcastle-Ottawa Scale). Pooled prevalence and 95% CI were calculated using a random-effects model in STATA 17. Heterogeneity (I²), subgroup analyses (by period, region, country), sensitivity analysis, and funnel plots for publication bias were performed.

Results

From 5,848 records, 48 studies (86,376 mothers; 2,875,104 infants) across 15 countries were included. The pooled MTCT prevalence was 7.0% (95% CI 5.2–9.4%; I² = 99.1%). Temporal trends showed a decline from 26.0% (1993–2000) to 8.0% (2001–2010) and 5.0% (2011–2023). Regionally, West Africa had the highest prevalence (12.1%; 95% CI 6.5–21.6%), Southern Africa had the lowest (4.7%; 95% CI 2.6–8.1%). Approximately 9% of HIV-exposed infants were infected by 24–48 months, 6% were infected by 24 months after enrolment, and 7% tested positive at their first HIV test conducted between 1 and 12 weeks of age.

Conclusion

Although MTCT rates have declined, the current 7.0% remains above the WHO target (<5%) with noted significant regional and national disparities. However, this rate should be interpreted cautiously due to the extremely high heterogeneity (I² = 99.1%) knowing it’s a directional synthesis of available evidence rather than a precise population-level figure.

Keywords

MTCT PMTCT HIV/AIDS sub-saharan Africa systematic review

1. Background

Reports from UNICEF, WHO, and UNAIDS in 2024 indicate that human immunodeficiency virus (HIV) infection remains a global public health concern. Over the past two decades (2000–2020), the number of individuals living with HIV worldwide increased significantly, reaching 39.9 million by 2023 with a noted rise of 1.2 million from 2020 and Africa accounting for 65% of cases.^1-3 Globally, approximately 1.2 million pregnant and breastfeeding women are living with HIV, of whom 84% have access to antiretroviral therapy (ART). Globally, vertical transmission of HIV in 2023 stands at 10% and approximately 78% of the 1.37 million children aged 0–14 who acquired HIV in the same year live in sub-Saharan Africa.^1-3 Mother-to-child transmission remains the primary source of HIV infection among children in sub-Saharan Africa.⁴ More than 9 out of 10 children under the age of 15 contract HIV through mother-to-child transmission (MTCT)⁵ and transmission can occur during pregnancy (in utero: 5–10%), labor and delivery (intrapartum: 15–25%), and breastfeeding (postpartum: approximately 16%).⁶

Recent programmatic reports from UNICEF indicate that substantial progress has been made in reducing mother-to-child transmission of HIV globally; however, important regional disparities persist, particularly in sub-Saharan Africa, where achieving elimination targets remains a challenge⁷. According to a country-level longitudinal ecological study by Feleke et al, it provided evidence that the rate of vertical HIV transmission in sub-Saharan Africa decreased from 27.18% to 16.9% between 2010 and 2019.⁸ In the same study, Southern Africa had the lowest MTCT rate in 2019 (4.44%). West Africa and East Africa recorded MTCT rates of about 17.5% in the same year, while Central Africa had the highest rate (18.75%).⁸ In contrast, a systematic review and meta-analysis conducted by Amare et al in Ethiopia found that the MTCT rate in East Africa was lower in 2020, at 7.68%.⁹ In 2019, South Africa, Namibia, and Botswana all had MTCT rates below 5%. More than 30% MTCT rates were reported in Djibouti, Madagascar, Somalia, and Sudan in the same year. Malawi recorded the largest annual MTCT rate decline with an estimate of 2.17% per year (95% CI: 1.55–2.79%), followed by Benin with an annual reduction of 2.07% (95% CI: 1.65–2.50%).⁸

Despite the documented decline in MTCT rates across sub-Saharan Africa, important gaps remain in the evidence base. First, there is substantial heterogeneity between sub-regions and countries, with Central and West Africa still reporting considerably higher transmission rates compared to Southern Africa. Second, estimates vary across studies due to differences in study design, data sources, time periods, and analytical approaches. For example, country-level ecological analyses may mask within-country disparities, while systematic reviews focused on specific regions may not provide a comprehensive sub-Saharan perspective. Against this backdrop, pooled national-level estimates of the overall prevalence of vertical HIV transmission across sub-Saharan Africa remain limited. Therefore, we conducted a systematic review and meta-analysis to determine the overall, time-trend, regional, and national prevalence of vertical transmission of HIV in sub-Saharan Africa.

2. Methods

2.1. Protocol and Registration

The current meta-analysis adhered to the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) and more recent PRISMA-S criteria.^9,10 As this study involved no primary data collection from human participants, institutional ethics approval was not required. The protocol was registered in PROSPERO (CRD42025637989).

2.2. Search Strategy

A systematic search was conducted across six electronic databases: MEDLINE (Ovid), Embase (Ovid), PubMed, Science Direct, Web of Science, and the Cochrane Library. Searches were restricted to articles published in English or French, with no restriction on publication date, to capture the full historical range of MTCT evidence in sub-Saharan Africa. The following key search terms were used in combination using Boolean operators (AND/OR): ‘mother-to-child transmission’, ‘vertical transmission’, ‘MTCT’, ‘PMTCT’, ‘HIV’, ‘AIDS’, ‘HIV-positive mothers’, ‘pregnant women’, ‘sub-Saharan Africa’, ‘Africa South of the Sahara’, and individual country names within the sub-Saharan African region. In addition to database searching, reference lists of all included studies and relevant systematic reviews were hand-searched to identify additional eligible studies. The complete database-specific search strategies, including all Boolean operators, truncations, and search limits used for each database, are provided in Supplementary File 1.

2.3. Study Duration and Selection

This study was conducted between June 2024 and May 2025. All records identified through database searches were exported to Rayyan, where duplicate entries were removed. Two independent reviewers (ERT and NNV) screened the titles and abstracts of the remaining records, with discrepancies resolved through consensus. Full-text articles were assessed for eligibility based on predefined inclusion and exclusion criteria.

Inclusion criteria: Studies were eligible if they: (1) used a cross-sectional, cohort, or case-control design; (2) were conducted in humans in sub-Saharan Africa; (3) involved HIV-positive pregnant women or women of reproductive age; (4) reported the prevalence or rate of vertical HIV transmission; and (5) were published in English or French.

Exclusion criteria: Studies were excluded if they were: (1) duplicate reports of the same dataset; (2) ongoing or unpublished trials; (3) case reports or case series; (4) randomized controlled trials, as they are not primarily designed to provide population-level prevalence estimates due to strict eligibility criteria and controlled conditions; or (5) qualitative studies, editorials, or commentaries.

2.4. Outcome Definition

The primary outcome of this review was the pooled mother-to-child transmission (MTCT) rate of HIV across studies, defined as the proportion of infants born to HIV-positive mothers who tested HIV-positive by any standard diagnostic method used at the time of the study. To account for the evolving standards of infant HIV diagnosis over the study period (1993–2023), we accepted all diagnostic approaches used in included studies and noted them during data extraction. Secondary outcomes included MTCT prevalence stratified by: (i) time period of the study, (ii) geographic region within sub-Saharan Africa, (iii) country, (iv) age at first HIV test, and (v) duration of follow-up after enrolment.

2.5. Data Extraction

Two authors (ERT and NNV) independently extracted data from each included study using a standardized data extraction form. Variables extracted included: author name; year of publication; study design; study location; follow-up duration; population and setting; sample size; and HIV transmission rate. Discrepancies were resolved through discussion. The primary outcome was the rate of HIV transmission from a mother living with HIV to her child.

2.6. Quality and Validity Assessment

Two review authors (NNV and ERT) independently assessed the methodological quality of all included studies¹¹. Cohort and case-control studies were appraised using the Newcastle–Ottawa Scale (NOS)¹², which rates studies across three domains: selection, comparability, and outcome assessment, yielding a maximum score of 9 stars. Studies scoring ≥7 stars were classified as good quality, those scoring 4–6 stars as fair quality, and those scoring ≤3 stars as poor quality. Cross-sectional studies were appraised using the Joanna Briggs Institute (JBI) critical appraisal checklist for prevalence studies, comprising nine items each scored as ‘Yes’ (1) or ‘No'/'Unclear’ (0). Studies achieving ≥85% of the total score were rated as high quality, 60–84% as moderate quality, and <60% as low quality. Only studies rated as moderate or high quality were eligible for inclusion. Disagreements between reviewers were resolved through discussion and, where necessary, by consulting a third reviewer. To assess the certainty of the evidence, we applied the GRADE (Grading of Recommendations, Assessment, Development and Evaluations) approach.¹³ GRADE evaluates evidence certainty across five domains: risk of bias, inconsistency, indirectness, imprecision, and publication bias. Since all included studies were observational, evidence was initially rated as low certainty and further downgraded by one level for serious concerns or two levels for very serious concerns within any domain. Final certainty ratings were classified as high (⊕⊕⊕⊕), moderate (⊕⊕⊕◯), low (⊕⊕◯◯), or very low (⊕◯◯◯). Risk of bias was informed by NOS and JBI appraisal scores. Inconsistency was assessed using the I² statistic. Indirectness reflected diversity in study populations, settings, time periods, and diagnostic methods. Imprecision was based on the width of 95% confidence intervals. Publication bias was assessed using Egger’s test and funnel plot inspection. The GRADE evidence profile covers five outcomes: overall pooled MTCT prevalence, temporal trends, regional variation, MTCT at first HIV test between 1 and 12 weeks of age, and cumulative MTCT by 24 months after enrolment (Table X). This approach is consistent with published HIV systematic reviews in sub-Saharan Africa.^14,15

2.7. Data Synthesis and Statistical Analysis

The prevalence of mother-to-child transmission (MTCT) of HIV was stratified by year of publication, geographic region within sub-Saharan Africa, and country of study. Statistical analyses were conducted using STATA version 17 software. Given the broad scope of the review, which spans three decades (1993–2023), includes 15 countries, and incorporates multiple study designs, substantial between-study heterogeneity was anticipated. Accordingly, a random-effects model was employed to estimate the pooled prevalence and corresponding 95% confidence intervals (95% CI). This model was selected because it accounts for both within-study and between-study variability and provides a more conservative summary estimate when heterogeneity is expected. Pooled prevalence estimates were calculated using inverse-variance weighting, and results were presented using forest plots. Statistical heterogeneity among studies was assessed using the I-squared (I²) statistic, with interpretation guided by the thresholds proposed by Higgins et al: no heterogeneity (I² = 0%), low heterogeneity (I² < 25%), moderate heterogeneity (I² = 25–50%), and high heterogeneity (I² > 75%).

To ensure robustness of the included evidence, study quality was assessed using the Newcastle–Ottawa Scale (NOS) for cohort and case-control studies and the Joanna Briggs Institute (JBI) critical appraisal checklist for cross-sectional studies, as described in Section 2.5. These assessments were used to evaluate the risk of bias and methodological rigor of the included studies, and only studies of moderate to high quality were retained for analysis. To explore potential sources of heterogeneity, subgroup analyses were conducted based on (i) period of publication, (ii) geographic region, and (iii) country of study. In addition, sensitivity analyses were performed by sequentially excluding individual studies with extreme effect sizes to assess their influence on the overall pooled estimate and evaluate the robustness of the findings. Publication bias was assessed using both visual and statistical methods. A funnel plot of study-level effect estimates against their standard errors was generated and inspected for asymmetry. In addition, Egger’s test for small-study effects was performed to provide a formal statistical assessment of funnel plot asymmetry. A p-value of less than 0.05 was considered indicative of statistically significant publication bias. Overall, the findings of this meta-analysis are interpreted as a weighted average of MTCT prevalence across diverse epidemiological settings, study designs, and programmatic contexts in sub-Saharan Africa, rather than as a single precise or universally generalizable estimate.

3. Results

3.1. Study Selection

The articles were retrieved by two authors (NNV and ERT). A total of 5,848 articles were retrieved from PubMed, Web of Science, Embase, MEDLINE, Science Direct, and the Cochrane Library. After retrieval, a total of 1,462 duplicate articles were excluded from the study. Following the duplicated articles removal, 4,386 articles were assessed based on the title, followed by the abstract. Among these articles, 4,156 were excluded. In addition, 104 articles were further assessed based on their full text, and 35 articles were obtained from citation searching. Finally, 139 studies were assessed based on the objectives, methods, and outcomes, of which 48 were included in the systematic review and meta-analysis (Figure 1).

Figure 1.

PRISMA flow diagram shows the study selection process used in the current study

3.2. Study Characteristics

A total of 48 studies conducted across 15 sub-Saharan African countries were included in the systematic review and meta-analysis (Figure 2). Among the included studies, 12 were conducted in Ethiopia (Asmamaw Ketemaw, Yirgalem Yosef, Hiluf Ebuy, Belay Birlie, Yibeltal Asmamaw, Mesfin Wudu Kassaw, Kidist Tadewos, Digsu Negese, Gebrehiwot Ayalew, Nurilign Abebe, Zelalem Berhan, and Destaye Guadie), two in Kenya (Martin Sirengo, Pratibha Datta), 7 in South Africa ((Ramraj et al, 2018), Appolonaire Tiam, David Coetzee, Felicity C, Hoosen M. Keshena Naidoo, and Simnikiwe H.), 5 in Cameroon (Patrice Tchendjou, Calixte Ida, Ahidjo Ayouba, Ahidjo Ayouba, Anne Esther), 3 in Zimbabwe (Victoria Ndarukwa, Lynn Sodai, and Lynn S.), 3 in Rwanda (Placidie Mugwaneza, Philippe Lepage, Marc Bulterys), 3 in Malawi (Michele A., Victor Mwapasa, Beth A.), 3 in Côte d’Ivoire (Besingin Towe-gold, Ehounou R., Georgette Adjorlolo-Johnson), 3 in Tanzania (Lyaatu Goodluck, Charles Kilewo and Fawzi Wafaie). See supplementary table 1 showing individual studies characteristics included and Figure 2 below mapping areas where selected studies were conducted.

Figure 2.

Map indicating the locations where the included studies were conducted Spatial data of the African continent and its country boundaries were obtained from GADM (www.gadm.org, accessed in 2024). The map was built using QGIS software to display the locations where the included studies were conducted. Country coordinates were identified based on study site information extracted during the systematic review process, and this figure was produced by the corresponding author.

In addition, a study was included from Nigeria (Ademola Joshua), 2 in Zambia (Kwasi Torpey and Kwasi Torpey), 1 in Burkina Faso (Thierry Prazuck), one in Congo (Marc Lallemant), one in Equatorial Guinea (Lius Manuel), and one in Uganda (Laurence Ahoua). The HIV transmission rate from mother to child ranged from 1% (Appolonaire Tiam) to 42.8% (Pratibha Datta) as showm on supplementary table 1.

The sample size of the included studies ranged from 13 to 28,338 and included pregnant women with HIV and infants/children/neonates, respectively. Among the included articles, 30 used a cohort study design, 15 articles used a cross-sectional study design, two studies used descriptive observational, and one study used prospective observational. The studies included in the current study were those published from 1993 to 2023 (Table 1).

Table 1.

Characteristics of Included Studies

Study characteristic	Value
Total studies	48
Publication period	1993 - 2023
Total HIV-positive pregnant women	73,185
Total infants/neonates	72,192
Study duration (months)	Mean: 28.6 (SD: 21.5, Range: 1.0-78.0)
Study designs	Cohort: 30 (62.5 %); Cross-sectional: 15 (31.2 %); Descriptive observational: 2 (4.2 %); Prospective observational: 1 (2.1 %)
Geographic distribution	13 studies in Central Africa, 20 studies in East Africa, 12 studies in Southern Africa, 3 studies in West Africa
Healthcare settings	Abidjan clinic: 1; Amhara referral hospitals: 1; Antenatal clinic: 1; Antenatal clinic and hospitals: 1; Antenatal clinics: 2; Arthur Davidson Children’s hospital: 2; Arua Regional Referral Hospital: 1; Banfora hospital: 1; Bata Regional hospital and Primary health center: 1; Butare haelth centers: 1; Caisse Nationale de Prevoyance Sociale hospital: 1; Community ART clinic: 1; Community-based antenatal clinics: 1; Dessie public health facilities: 1; Essos Central hospital: 1; Gondar health centers and hospital: 2; Gondar University referral hospital PMTCT clinic: 1; Harare city health polyclinics: 1; Health centers: 1; Health facilities: 1; Health facility: 1; HIV clinics: 1; Hospitals: 1; Immunization clinics: 1; Jimma University Specialized Hospital PMTCT clinic: 1; Local authority clinics: 1; Mabvuku Polyclinic: 2; Major maternity hospital: 1; Maternaland child health center: 1; Maternity Ward of the Centre Hospitalier de Kigali: 1; Medium or high volume health centers: 1; Mekelle public hospitals: 1; midwife-run obstetric unit: 1; NASCOP programmatic regions’ households: 1; PMTCT clinic of the University of Gondar specialized hospital: 1; PMTCT HIV clinic: 1; Primary health care antenatal clinics: 1; Public and faith-based primary health care facilities: 1; Queen Elizabeth Central Hospital: 1; Referral hospitals: 1; Sidama public health facilities: 1; South Omo Pastoralist Health Facilities: 1; Specialist Hospital Yola and Federal Medical Centre Yola: 1; Under-5 vaccination or outpatient sick-child clinic: 1
Sample size distribution	Median: 366 (IQR: 205-657, Range: 13-28320)

3.3. Prevalence of Mother-To-Child Transmission of HIV

The pooled MTCT of HIV across sub-Saharan Africa was 7.0% (95% CI: 5.2%–9.4%), (Figure 3). This pooled prevalence reflects a weighted average across highly diverse settings rather than a single universally generalizable estimate and interpretation and this estimate should be interpreted cautiously due to the extremely high heterogeneity (I² = 99.1%).

Figure 3.

The forest plot shows an overall pooled prevalence of HIV transmission from the mother to the child in the African Region, 2024

The very high heterogeneity observed (I² = 99.1%) indicates substantial between-study variability in MTCT prevalence, which is expected given the wide range of study periods (1993–2023), geographic settings, study designs, and PMTCT program contexts represented. Consequently, the pooled estimate of 7.0% is interpreted with caution, as it reflects an average across highly diverse contexts rather than a single generalizable estimate.

Based on the subgroup analysis based on the publication year, the highest pooled prevalence of HIV transmission from mother to child was reported from 1993 to 2000, which accounted for 26.0% (95% CI: 19, 36%). The lowest pooled prevalence of HIV transmission from mother to child was reported between 2011 and 2023, accounting for 5% (95% CI: 3, 7%), which indicates the decline in HIV transmission from mother to child (Supplementary Figure 1).

Based on the subgroup analysis employed, based on the different parts of Africa Region, the highest overall prevalence HIV transmission from mother to child was reported in West Africa, accounting for 12.1% (95% CI: 6.5–21.6%), followed by the prevalence in Central Africa, accounting for 8.4% (95% CI: 3.9–17.2%). However, the pooled lowest prevalence of HIV transmission from the mother to the child was reported in Southern Africa, accounting for 4.7% (95% CI: 2.6, 8.1%) (Supplementary Figure 2).

Based on subgroup analysis by country of study, high prevalence rate was recorded in Kenya, at 27% (95% CI: 8.3% to 60.1%). The lowest prevalence was reported in Zimbabwe, at 2.1% (95% CI: 1.5, 2.9%). The pooled prevalence of HIV transmission from mother to child in Cameroon, Ethiopia, and South Africa was 6.7% (95% CI: 3.8, 11.4%), 6.9% (95% CI: 5.2, 9.1%), and 4.5% (95% CI: 2.0, 9.9%), respectively (Supplementary Figure 3).

About 6% of exposed infants were infected by 24 months (95% CI: 4.4-8.1%). This rose to roughly 9% among HIV-exposed children between 24 and 48 months (95% CI: 4.6-15.2 %). Overall, across the included studies, around 10% (95% CI: 6.4-15.3 %) of children born to HIV-positive mothers had acquired HIV by four years of age or later (Supplementary Figure 5).

Approximately 7% (95% CI: 5.0-97 %) of HIV-exposed infants tested positive at their first HIV test conducted between 1 and 12 weeks of age, compared with about 8% (95% CI: 4.4-14.4 %) of those first tested after 12 weeks (Supplementary Figure 6).

Across the included studies, about 6% (95% CI: 4.2-8.9%) of HIV-exposed infants became infected by 24 months after enrolment. This increased to nearly 18% by 24–48 months (95% CI: 6.9 - 38.8 %) of follow-up, while approximately 9% (95% CI: 5.6-14.5) were infected at ≥48 months (Supplementary Figure 7).

3.4. Risk of Bias

Among the 33 cohort studies assessed using the Newcastle–Ottawa Scale, 61% were rated as good quality and 39% as fair quality. Of the 15 cross-sectional studies appraised using the JBI checklist, 67% were rated as high quality, 27% as moderate quality, and 6% as low quality. (Supplementary Table 2).

3.5. Sensitivity Analysis

Meta-regression was conducted despite heterogeneity, but a sensitivity analysis was employed by excluding the extreme values or outcomes expected to influence the overall pooled rate of HIV transmission from mother to child in the African region. However, there was no substantial or significant difference between the results before and after the sensitivity analysis (Supplementary Table 3).

3.6. Publication Bias and Heterogeneity

As presented in the supplementary Figure 4, publication bias was assessed using funnel plots and Egger’s regression test (p < 0.001) suggesting possible underreporting of higher transmission rates. Sensitivity analyses excluding lower-quality studies did not substantially alter the main findings, supporting the robustness of the results.

3.7. Grade Evidence Profile

The GRADE evidence profile for the five key outcomes of this review is presented in supplementary table 4. All five outcomes were derived from observational studies and therefore started at a baseline certainty of low, consistent with GRADE guidance for non-randomised evidence. The overall pooled MTCT rate of 7.0% (95% CI: 5.2–9.4%) was rated as very low certainty (⊕◯◯◯), following downgrading across all five GRADE domains. Risk of bias was considered serious, as 39% of cohort studies were rated only fair quality and 6% of cross-sectional studies were rated low quality on their respective appraisal tools. Inconsistency was rated very serious, reflecting the extremely high statistical heterogeneity observed across included studies (I² = 99.1%), which could not be fully explained by the subgroup analyses conducted. Indirectness was rated serious, as the included studies spanned three decades (1993–2023), 15 countries, and multiple PMTCT policy eras, with varying diagnostic methods used to define the outcome across study periods. Imprecision was rated serious given the wide 95% confidence interval around the pooled estimate. Publication bias was strongly suspected based on significant Egger’s test results (p < 0.001) and funnel plot asymmetry.

The certainty of evidence for regional subgroup estimates (West Africa: 12.1%; Central Africa: 8.4%; East Africa: 7.7%; Southern Africa: 4.7%) was also rated as very low (⊕◯◯◯), primarily due to very serious inconsistency within regional subgroups, serious indirectness from uneven country representation, and wide confidence intervals. Temporal trend estimates were rated as low certainty (⊕⊕◯◯), the highest rating achieved in this review, as the directional consistency of the decline across the three policy eras from 26.0% (1993–2000) to 8.0% (2001–2010) and 5.0% (2011–2023) partially offset concerns about heterogeneity and indirectness. The MTCT estimate at first HIV test conducted between 1 and 12 weeks of age (7%; 95% CI: 5.0–9.7%) and the cumulative MTCT estimate by 24 months after enrolment (6%; 95% CI: 4.4–8.1%) were both rated as very low certainty (⊕◯◯◯), due to serious concerns across risk of bias, inconsistency, indirectness, and imprecision domains, and suspected publication bias. These very low certainty ratings across most outcomes reflect the inherent limitations of a broad MTCT rate review spanning diverse settings and a long time period, and underscore the need for cautious interpretation of the pooled estimates.

4. Discussion

The overall pooled MTCT rate in sub-Saharan Africa was 7.0%, although substantial variation was observed across countries. A declining trend of MTCT of HIV was observed in the last three decades, from 26% (1993-2000) to 8% (2001-2010) and finally to 5% (2011-2023). The hardest hit region of sub-Saharan Africa was West Africa (12.1%), followed by Central Africa (8.4%), whereas the least affected were Southern Africa (4.7%) and East Africa (7.7%). Across the included studies, approximately 9% of HIV-exposed infants were infected by 24-48months, 6% by 24 months after enrolment, and 7% tested positive at their first HIV test, conducted between 1 and 12 weeks of age. To identify significant changes to PMTCT interventions over the past years, studies were grouped into three periods (1993–2000, 2001–2010, and 2011–2023). These periods align with major PMTCT policy’s adoptions and implementation respectively seen as the pre-PMTCT era with limited access to ART and high transmission rates, the scale-up of ART prophylaxis with evidence from trails such as the HIVNET-012 and the progressive expansion of the PMTCT programs in early 2000s, and the rapid and widespread era of ART backed up with the adoption of sustainable ART strategies such as Option B+.^16-18 Also, many countries reported decline in MTCT following the rapid expansion of the PMTCT programs and the increasing maternal ART coverage^19,20. Therefore, grouping studies within these different eras improve statistical stability and allow comparisons of MTCT rate across major policy and treatment milestones in the global HIV response framework and coverage periods^16,17.

The obtained transmission rate of 7% aligns with a systematic review conducted by Belachew et al highlighting despite actual progress made in lowering transmission rates compared to past centuries they are still above the 5% targeted by global elimination goals.²¹ This results also match a similar study that was published by Ka’e AC et al showing MTCT was 7.00% (95% CI = 6.07–8.51) with PMTCT Option-B+ resulting in about 25% reduction of MTCT.²² However, this result was contradictory compared to another systematic review and meta-analysis conducted in Ethiopia which demonstrated a pool MTCT rate of 4.05%.²³ This could be explained by the period of included studies which ranges from 1993-2023 in our study while in the contradictory study it covers 2013-2023 thereby highlighting intervention gaps and innovative interventions which influences MTCT rate over time. From a clinical and programmatic perspective, this implies that the 7% pooled MTCT estimate should not be interpreted as an expected transmission risk for any specific country, facility, or patient population. Instead, it represents an aggregated regional benchmark reflecting varying levels of PMTCT effectiveness across time and settings. Therefore, clinical decision-making and program planning should rely more on context-specific estimates and local PMTCT performance indicators (such as maternal viral suppression rates and early infant diagnosis coverage), rather than this overall pooled estimate alone.

The observed declining trend in MTCT over the past three decades, from 26% (1993-2000) to 8% (2001-2010) and finally to 5% (2011-2023) is likely attributable to the scale-up of ART within the sub-Saharan African region as supported by Ka’e et al, who reported a 25% reduction in MTCT,²² and by Belay et al, who demonstrated MTCT rates below 5% following widespread implementation of Option B+.²⁴ Similarly, several African reports mentioned a reduced transmission rate due to the introduction of ART in late 1990s and early 2000s.²⁵ This is further supported by WHO estimates indicating that, in the absence of any intervention, the rate of HIV transmission from a mother to her child ranges from 15% to 45%.²⁶ Moreover, country level program MTCT evaluation like in Uganda showed a decline rate from 16.9% in 2000s to 3% by 2020.²⁴ Despite this progress, important health system gaps persist when compared with high-income countries such as the United States and the United Kingdom in which PMTCT strategies are included universal antenatal HIV screening, early initiation of combination antiretroviral therapy, optimized obstetric care, and appropriate infant prophylaxis which has resulted in dramatic reductions in transmission rates of 1–2%.^27-29

Regional difference observed in Southern African countries demonstrated the lowest transmission rates (4.7%), followed by East Africa (7.7%), Central Africa (8.4%) and West Africa (12.1%) was pinpointed by Belay et al in Ethiopia reporting a similar pooled rate of 7.68% in East Africa.²⁴ UNICEF reported that West Africa and Central Africa account for a vertical HIV transmission of 21% in 2022 with PMTCT coverage at 52%.³⁰ These findings underscore the need for a dramatic scale-up of HIV treatment coverage among pregnant and breastfeeding women living with HIV. Coverage with ARVs among pregnant women living with HIV has reached 94% in Eastern and Southern Africa and reduction to new HIV infection in children by 72% by 2010. More to that, ARV coverage in West and Central Africa was at 54% and almost half of pregnant and breastfeeding women living with HIV in West and Central Africa were not receiving ARVs in 2023.²¹ Early infant diagnosis coverage in Eastern and Southern Africa reached 79% in 2023 (exceeding 90% in some countries), but it was 26% in West and Central Africa. Access to oral PrEP among adolescent girls and young women has increased markedly in Eastern and Southern Africa in recent years.²¹ All these regional disparities could be due to cultural differences, variations in stakeholder engagement and differences in health systems capacity across these regions.

The 7% of HIV exposed infants tested positive at their first HIV test conducted between 1-12 weeks reflects in utero and intrapartum transmission which generally occurs during or before delivery. This finding is consistent with evidence from sub-Saharan Africa demonstrating that MTCT risk increases significantly in the absence of adequate viral load monitoring and adherence support.^31-34 The 6% of exposed infants infected by 24 months and 9% by 24-48 months could reflect a post-partum transmission because of retention gaps, maternal adherence being inconsistent and rise in maternal viral load. Results from two longitudinal cohort studies demonstrated a substantial increase in MTCT during breast feeding when maternal viral load suppression is not achieved. Therefore, there is need to strengthen retention in care and providing support for breasting to reduce postnatal transmission.^35,36

These findings differ from surveillance data reported in high-income countries, where early infant HIV infection rates within 1 week of birth are considerably lower: United States (1%), United Kingdom (1%) and France (0.5-1%) reflecting aside from other interventions a high maternal treatment coverage and effective obstetric management.^28,29,37

The substantial heterogeneity observed across the included studies (I² = 99.1%) is likely attributable to multiple methodological, temporal, and contextual differences. First, the studies spanned a broad period from 1993 to 2023, encompassing major changes in HIV prevention strategies and PMTCT program implementation over time. These periods reflect distinct PMTCT policy eras, including the pre-ART era, the introduction of prophylactic antiretroviral regimens, and the widespread implementation of lifelong ART strategies such as Option B+. Second, important geographic and health-system differences exist across sub-Saharan Africa, particularly in access to maternal ART, viral load monitoring, early infant diagnosis, retention in care, and healthcare infrastructure. Third, the included studies varied in design, including cross-sectional, cohort, and observational approaches, each with different sampling methods and risk of bias profiles. Furthermore, infant follow-up duration differed considerably between studies, with some assessing HIV status within the first weeks of life and others reporting outcomes up to 48 months or later, thereby capturing different periods of transmission risk including intrapartum and breastfeeding transmission. Finally, variations in ART coverage, PMTCT implementation fidelity, and local clinical practices across countries and time periods may have further contributed to the observed between-study variability. Consequently, the pooled estimate should be interpreted as a summary across diverse epidemiological and programmatic contexts rather than a single precise population-level estimate.

Strengths and Limitations: To our knowledge, this is one of the first systematic reviews and meta-analyses to provide a pooled estimate of MTCT prevalence across sub-Saharan Africa. Aside from this, our manuscript provides an updated and comprehensive synthesis of evidence, incorporating the most recent data across sub-Saharan Africa, which reflects current trends in vertical transmission in the context of evolving PMTCT strategies. Secondly, we provide time-trend analyses, allowing for a better understanding of how transmission rates have changed over time, particularly in response to policy shifts and programmatic interventions. Importantly, our findings provide critical empirical insights into transmission dynamics across the continuum of care. We observed that approximately 7% of HIV-exposed infants tested positive at their first HIV test conducted between 1–12 weeks of life, while about 9% were infected by 24-48 months and 6% by 24 months after enrolment. These findings highlight persistent early and postnatal transmission risks, underscoring gaps in both early infant diagnosis and sustained PMTCT follow-up, an aspect insufficiently detailed in previous reviews. Thirdly, our study includes regional and national-level estimates, highlighting heterogeneity across countries and regions that is critical for informing targeted interventions and policy decisions. However, high heterogeneity (I² > 99%), potential publication bias, and underrepresentation of other studies in sub-Saharan countries like Congo may have limited external/internal validity of our findings. While subgroup analyses by period, region, and country were conducted to explore these sources of variation, residual heterogeneity remains. Consequently, the pooled estimate should not be interpreted as a precise population-level figure but rather as a directional synthesis of available evidence. The uneven representation of countries with Ethiopia and South Africa contributing disproportionately more studies than others may further limit the generalizability of regional and national estimates. Language restrictions to English and French could have omitted relevant studies.

5. Conclusion

Despite substantial progress over the past three decades, MTCT in sub-Saharan Africa remains above the WHO elimination target, with a pooled prevalence of 7.0%. This finding must be interpreted with caution as high heterogeneity (I² = 99.1%) across included studies reflects substantial diversity in time periods, study designs, geographic settings, and programmatic contexts, limiting the precision and generalizability of the pooled estimate. Uneven country representation with some countries contributing disproportionately more studies may further affect the reliability of regional and national comparisons. The decline of MTCT over the recent years reflects the impact of ART scale-up and particularly Option B+. However, it’s to be noted that some implementation gaps are observed in West and Central regions of Africa compared to others African regions inline to early infant diagnosis, maternal viral load monitoring, and retention in care. Therefore, it is essential to optimize PMTCT program implementation, engage relevant stakeholders at all levels, and expand equitable access to comprehensive PMTCT services to achieve the global HIV elimination targets.

Supplemental Material

Supplemental material -Time-Trend, Regional and National Prevalence of Vertical Transmission of HIV-1 in Sub-Saharan Africa: A Systematic Review and Meta-Analysis

Supplemental material for Time-Trend, Regional and National Prevalence of Vertical Transmission of HIV-1 in Sub-Saharan Africa: A Systematic Review and Meta-Analysis by Misonge Kapnang Ivan, Njongang Vigny Njeodo, Solange Youdom Whegang, Joseph Fokam, Esoh Tanwieh Rene, Charles Kouanfack, and Donatien Gatsing in Journal of Primary Care & Community Health.

Supplemental Material

Supplemental material -Time-Trend, Regional and National Prevalence of Vertical Transmission of HIV-1 in Sub-Saharan Africa: A Systematic Review and Meta-Analysis

Supplemental Material

Supplemental material -Time-Trend, Regional and National Prevalence of Vertical Transmission of HIV-1 in Sub-Saharan Africa: A Systematic Review and Meta-Analysis

Supplemental Material

Supplemental material -Time-Trend, Regional and National Prevalence of Vertical Transmission of HIV-1 in Sub-Saharan Africa: A Systematic Review and Meta-Analysis

Supplemental Material

Supplemental material -Time-Trend, Regional and National Prevalence of Vertical Transmission of HIV-1 in Sub-Saharan Africa: A Systematic Review and Meta-Analysis

Supplemental Material

Supplemental material -Time-Trend, Regional and National Prevalence of Vertical Transmission of HIV-1 in Sub-Saharan Africa: A Systematic Review and Meta-Analysis

Supplemental Material

Supplemental material -Time-Trend, Regional and National Prevalence of Vertical Transmission of HIV-1 in Sub-Saharan Africa: A Systematic Review and Meta-Analysis

Supplemental Material

Supplemental material -Time-Trend, Regional and National Prevalence of Vertical Transmission of HIV-1 in Sub-Saharan Africa: A Systematic Review and Meta-Analysis

Supplemental Material

Supplemental material -Time-Trend, Regional and National Prevalence of Vertical Transmission of HIV-1 in Sub-Saharan Africa: A Systematic Review and Meta-Analysis

Footnotes

Acknowledgements

The authors would like to thank all researchers whose studies were included in this systematic review and meta-analysis. Their contributions made this work possible.

ORCID iD

Misonge Kapnang Ivan

Ethical Considerations

This study does not involve human participants, and ethical approval was not required to conduct this study because it uses articles previously published.

Author Contributions

MKI developed protocol and refined it with ERT and NNV. NNV wrote the initial draft conducted the data analysis. GD, KC, SW, FJ, and IM contributed to subsequent drafts. All authors edited and approved the final manuscript.

Funding

The authors received no financial support for the research, authorship, and/or publication of this article.

Declaration of Conflicting Interests

The authors declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Data Availability Statement

The datasets used and/or analyzed during the current study available from the corresponding author on reasonable request.*

Supplemental Material

Supplemental material for this article is available online.

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