Prevention of HBV Mother‐To‐Child Transmission (MTCT) Using Targeted HBV Birth Dose, and Treatment of High Viral Load Pregnant Women in Uganda

ABSTRACT

Hepatitis B virus (HBV) mother‐to‐child transmission (MTCT) remains a major challenge in Uganda, where 43% of births occur at home, and access to timely birth dose (BD) vaccination is limited. We evaluated the impact of combining universal three‐dose (3D) infant vaccination, targeted BD vaccination, and maternal antiviral treatment for high viral load (HVL) mothers on HBV prevalence among infants. In a prospective 18‐month cohort study at five regional maternity hospitals, HIV‐negative pregnant women were screened for HBsAg. HBsAg‐positive mothers were stratified by HBV DNA into HVL (≥ 20,000 IU/mL), low viral load (LVL), or LVL on treatment. HVL mothers received Tenofovir Disoproxil Fumarate plus Lamivudine in the third trimester. Infants of HBsAg‐positive mothers received BD vaccination within 24 h and the 3D pentavalent series; infants of HBsAg‐negative mothers received the 3D series only. All infants were tested for HBsAg at nine months. Of 19,053 mothers screened, 3.46% were HBsAg‐positive (n = 660). Among HVL mothers (n = 80), 96.3% initiated antivirals; none of their infants who received both BD and 3D tested HBsAg‐positive. Among LVL mothers not on treatment (n = 558), the prevalence of infection at nine months was 0.4% despite full vaccination. No infections occurred among LVL mothers on treatment or among infants of HBsAg‐negative mothers. Overall infant HBsAg prevalence was 0.19%, with an adjusted national estimate of 0.02%. Integrating maternal antiviral prophylaxis, targeted BD vaccination, and universal 3D vaccination achieved near‐elimination of HBV MTCT in this setting. Nationally scaling this strategy could enable Uganda to meet the WHO target of less than 0.1% infant HBV prevalence before 2030 and serve as a model for other high‐burden countries with significant rates of home births.

Abbreviations

3D

HBV three‐dose vaccination

3TC

Tenofovir disoproxil fumarate and lamivudine

BD

Birth dose vaccination

HBV

Hepatitis B virus

HVL

High viral load

LVL

Low viral load

MTCT

Mother to child transmission

PCR

Polymerase chain reaction

TDF

Tenofovir disoproxil fumarate

UNEPI

Uganda's National Expanded Program on Immunisation

WHO

World Health Organization

1. Introduction

Hepatitis B virus (HBV) infection remains highly endemic in Uganda, with a national prevalence of 5% and regional studies reporting prevalence as high as 11.8% among pregnant women [1, 2]. In high‐endemic regions like Uganda, HBV transmission occurs primarily through mother‐to‐child transmission (MTCT) during the perinatal period. Approximately 90% of infants born to hepatitis B surface antigen (HBsAg)‐positive mothers develop chronic infection without intervention [3, 4, 5, 6, 7]. The consequences are severe, as chronic HBV infection acquired in infancy carries a 15%–25% lifetime risk of premature death from cirrhosis and hepatocellular carcinoma [5, 7, 8].

The World Health Organization recommends hepatitis B vaccination within 24 h of birth to prevent MTCT, followed by completion of the primary vaccination series [9]. For mothers with high viral loads (≥ 20,000 IU/mL), antiviral therapy during pregnancy combined with timely infant vaccination can reduce transmission by 75%–90% [10, 11, 12]. However, routine screening of pregnant women for HBsAg and administration of birth dose (BD) vaccine to exposed infants is not standard practice in Uganda [2].

Uganda's National Expanded Program on Immunisation (UNEPI) introduced HBV vaccination in 2002; however, the first dose is administered at six weeks as part of the pentavalent vaccine, reducing its effectiveness in preventing vertical transmission and leaving a critical window for transmission through close contact [5, 6, 13, 14, 15]. Despite achieving 90% coverage of the three‐dose series since 2013, this delayed approach remains inadequate for preventing perinatal transmission [16, 17]. Universal BD vaccination was introduced in Uganda in 2023, but access remains limited outside major cities [18]. This challenge is compounded by the fact that approximately 43% of Uganda's annual 1.7 million births occur at home, creating barriers to timely intervention [19].

Given these persistent challenges in preventing MTCT in Uganda, this study examines the effectiveness of a comprehensive prevention strategy combining maternal antiviral treatment for women with high viral loads, universal three‐dose infant vaccination, and targeted birth dose in reducing HBV prevalence among infants.

2. Methods

2.1. Study Design

This was a prospective cohort study conducted over 18 months across five hospitals—one national (Kawempe) and four regional (Arua, Gulu, Jinja, Mbarara) maternity hospitals in Uganda (Figure 1). The study evaluated strategies to reduce MTCT through combined implementation of antiviral treatment during late‐stage pregnancy, targeted HBV birth dose vaccination for infants born to HBV‐positive mothers, and universal pentavalent three‐dose infant vaccination.

FIGURE 1.

Map of National and Regional Testing Sites.

2.2. Study Population

HIV‐negative pregnant women attending prenatal care at the selected hospitals and able to provide informed consent were enrolled in the study, with a total of 19,053 participants screened. The exclusion criterion was based on evidence of liver decompensation (ascites, encephalopathy, wasting, or hepatorenal syndrome), a diagnosis of active hepatocellular carcinoma (HCC), current dialysis treatment, or HBsAg/HIV co‐infection. Participants identified with co‐infection were referred to specialised integrated HIV‐HBV care services. Infants delivered by both HBsAg‐positive and HBsAg‐negative enrolled mothers constituted the secondary study cohort.

2.3. Sampling and Screening Procedure

Over a nine‐month period, pregnant women attending routine prenatal care visits were systematically screened using rapid diagnostic tests for HBsAg (Abbott Determine HBsAg 2 test) and HIV (The Abbott Bioline HIV/Syphilis Duo test). HIV‐positive women were excluded and referred to specialised care.

HBsAg‐positive participants underwent additional HBV DNA viral load testing using polymerase chain reaction (PCR) testing on the CAP/CTM HBV v2.0 Assays at the National Health Laboratory and Diagnostic Services (NHLDS) centre. Participants were stratified into three groups: High viral load (HVL: HBV DNA ≥ 20,000 IU/mL) eligible for antiviral treatment, low viral load (LVL: HBV DNA < 20,000 IU/mL), and LVL participants already receiving antiviral therapy. The limit of quantification (LLOQ) for the Cobas CAP/CTM HBV Test v2.0 is 20 IU/mL. This version of the test has a dynamic range of quantification from 20 to $1.7\times {10}^8$ IU/mL, and a limit of detection (LOD) of 9.0 IU/mL in plasma.

2.4. Interventions and Data Collection

After obtaining informed consent, maternal rapid test results were documented in real‐time. Blood specimens from HBsAg‐positive mothers were collected on‐site and transported to NHLDS for HBV DNA quantification.

High viral load mothers received antiviral treatment consisting of 300 mg/day Tenofovir Disoproxil Fumarate (TDF) in combination with 150 mg Lamivudine (3TC) for three months during the third trimester, with adherence monitored through monthly telephone follow‐up by research coordinators. These mothers underwent a follow‐up blood draw at three months postpartum to assess for viral load flare‐ups.

All infants born to HBsAg‐positive mothers received the HBV BD vaccine within 24 h of birth, followed by the standard pentavalent three‐dose vaccination schedule. Infants born to HBsAg‐negative mothers received only the standard pentavalent vaccination. Vaccination records were documented and verified through the clinic's immunisation records. At the routine nine‐month measles vaccination visit, all infants underwent HBsAg rapid testing. An estimated 10% loss to follow‐up was anticipated.

2.5. Data Management

HBV viral load data were archived and downloaded from the NHLDS, while other participants' level data were collected and managed using the Research Electronic Data Capture (REDCap) hosted at secure cloud‐based servers at the Makerere Lung Institute (MLI). Participants' data access was restricted to treating physicians, nurses, and system administrators. All devices were password‐protected and individually assigned to healthcare providers, with encrypted communication to the secure cloud‐based database. Participants' personal identifiers were encrypted, with viewing access limited to system administrators. Only aggregate data were reported publicly.

2.6. Data Analysis

Analysis was conducted using Microsoft Excel and focused primarily on demonstrating an HBsAg prevalence of less than 0.1% among infants at nine months of age, aligning with the WHO's HBV MTCT elimination target. Infant outcomes were stratified by maternal HBV viral load category and treatment status. Secondary analyses assessed HBsAg prevalence among all infants who received both the HBV BD vaccine and the pentavalent vaccinations. Adjustments incorporated anticipated loss to follow up, with monitoring of adherence to interventions and timing of vaccinations and treatments.

3. Results

3.1. Maternal HBsAg Prevalence

Of the 19,053 mothers screened, 660 tested positive for HBsAg, corresponding to an overall prevalence of 3.5% (Table 1). Regional distribution showed the highest proportions of mothers were recruited from Kawempe (33.4%) and Arua (28.5%), though the highest HBsAg prevalence was observed in the Gulu region (5.5%). The profile of the HBsAg‐positive mothers by region is shown in Table 2.

TABLE 1.

Regional prevalence distribution.

	Arua	Gulu	Jinja	Kawempe	Mbarara	Total
Mothers Screened	5,441	3,059	2,635	6,372	1,556	19,063
HBsAg+ Mothers	193	167	89	153	58	660
HBsAg Prevalence	3.55%	5.46%	3.38%	2.40%	3.73%	3.46%

TABLE 2.

Regional characteristics and epidemiology of HBsAg‐positive pregnant women.

Site	HBsAg+ Mothers	Average Age (Range)	Mother Vaccinated (%)			Aware of HBV Status (%)	Treated with TDF (%)	High Viral Load (%)	Infants Born
			Yes	No	Unsure
Arua	193	28 (16–41)	0 (0.0%)	26 (13.5%)	167 (86.5%)	80 (41.5%)	17 (8.8%)	25 (13.0%)	182
Gulu	167	28 (19–42)	76 (45.5%)	72 (43.1%)	19 (11.4%)	77 (46.1%)	7 (4.2%)	23 (13.8%)	130
Jinja	89	27 (17–40)	7 (7.9%)	76 (85.4%)	6 (6.7%)	20 (22.5%)	4 (4.5%)	11 (12.4%)	85
Kawempe	153	28 (16–43)	21 (13.7%)	114 (74.5%)	18 (11.8%)	2 (13.1%)	7 (4.6%)	14 (9.2%)	102
Mbarara	58	30 (19–45)	0 (0.0%)	46 (79.3%)	12 (20.7%)	17 (29.3%)	1 (1.7%)	7 (12.1%)	55
Total	660	28 (16–45)	104 (15.8%)	334 (50.6%)	222 (33.6%)	214 (32.4%)	36 (5.5%)	80 (12.1%)	554

Among the 660 HBsAg‐positive mothers, 80 (12.6%, 95% CI: 9.6%–14.6%) were classified as having HVL, while 558 (84.5%, 95% CI: 81.8%–87.3%) had LVL (Figure 2). Additionally, 11 (1.7%, 95% CI: 0.7%–2.6%) mothers were already receiving antiviral treatment prior to enrollment. A cohort of 666 HBsAg‐negative mothers was also recruited to measure the MTCT among HBV‐negative mothers.

FIGURE 2.

Project Patient Flow.

3.2. Treatment Implementation and Follow‐Up

Among the 80 mothers identified with HVL, 77 (96.3% 95% CI: 92.1%–100%) initiated antiviral treatment during the third trimester. For infants who initiated the three‐dose vaccine series, compliance for all three doses exceeded 90%.

Loss to follow‐up among mothers occurred predominantly during the pentavalent phase, primarily due to lost contact and no telephone access (n = 44). Additional losses among infants (n = 30) were attributed to miscarriage, neonatal death, and termination of pregnancy.

3.3. Infants HBsAg Outcomes

Among infants born to the 77 HVL mothers who received antiviral treatment combined with BD vaccination within the first 24 h and the complete three‐dose vaccination series, none tested positive at nine months. However, among the 3 HVL mothers who did not initiate antiviral treatment, one infant tested HBsAg‐positive after receiving HBV BD vaccination but did not complete the three‐dose series.

Among the 558 LVL mothers not already on treatment, 471 infants were delivered. Two infants (0.4%) tested positive for HBsAg at nine months despite having received the HBV birth dose and completing the full pentavalent vaccine schedule. However, none of the infants born to LVL mothers already on antiviral treatment tested positive.

None of the tested infants born to HBsAg‐negative mothers were found to be infected at the nine‐month follow‐up.

The overall loss to follow up was 256 cases (39%), with most mothers lost after the infant was born (n = 95), followed by infants not showing up for their nine‐month HBsAg test (n = 76). If an infant initiated HBV pentavalent vaccination (lost to follow‐up of 5.1% for the first dose), the loss to follow‐up was less than 2% for the second and third doses.

3.4. Overall Infant Infection Rate

The overall prevalence of HBsAg among all tested infants in the study was 0.19%. Among infants born specifically to LVL mothers not receiving antiviral treatment, the prevalence was 0.6% (95% CI: 0%–1.4%). After accounting for 96.5% of mothers who tested negative in the cohort, the adjusted prevalence of HBsAg infection among all infants was 0.02% (95% CI: 0%–0.4%), below the WHO‐recommended target of 0.1%.

4. Discussion

This study demonstrates that a combined strategy of maternal antiviral prophylaxis for HVL mothers, targeted BD vaccination for exposed infants, and universal completion of the three‐dose hepatitis B vaccination series can achieve near‐elimination of HBV MTCT in a high‐endemic setting. Among infants born to HVL mothers who received antiviral therapy and timely BD vaccination, no cases of HBV infection were detected at nine months. Even when including all infants tested, the adjusted prevalence of HBsAg was 0.02%, well below the WHO elimination target of < 0.1% for MTCT [9]. These findings provide strong evidence that the integration of targeted maternal and infant interventions into prenatal and delivery care is both feasible and highly effective in Uganda.

The overall maternal HBsAg prevalence in this cohort (3.46%) is lower than earlier reports from Uganda, where prevalence among pregnant women has ranged from 2.1% to 11.8% depending on region and year [2, 20, 21, 22]. The lower prevalence in our study may reflect regional differences, the exclusion of HIV co‐infected mothers, or the shift in epidemiology following increased routine infant vaccination since 2002 [15]. Nevertheless, the burden remains within the intermediate endemicity category, and without targeted MTCT prevention, perinatal HBV transmission risk can range from 10% to 40% [23].

Our infant infection outcomes compare favourably to other studies in sub‐Saharan Africa. TDF‐based prophylaxis initiated in late pregnancy, combined with timely neonatal immunisation, has been shown to reduce MTCT by 75%–90% [10, 11, 12], with some studies reporting residual infection rates of 5%–10% [24]. The complete absence of infection among the infants of treated HVL mothers in our study likely reflects the high uptake of antivirals (96.3%), adherence monitoring through monthly follow‐up, and rigorous BD administration within 24 h [25, 26]. The rare cases of infection among low viral load mothers, despite BD and full vaccination, have been documented elsewhere, suggesting that maternal viral load alone may not fully predict transmission risk [27, 28].

Prevention of MTCT in HVL mothers is largely mediated by maternal viral load suppression at delivery. HBV DNA levels ≥ 20,000 IU/mL are strongly associated with increased MTCT risk [10], and short‐course tenofovir in the third trimester is both safe and effective at reducing maternal viral load to levels at which passive‐active immunisation is more likely to succeed [9, 25, 29]. For LVL mothers, timely BD and completion of the pentavalent series provide high levels of protection, but breakthrough infections remain possible, suggesting that transmission risk may not be fully eliminated at lower viral loads. These findings are consistent with calls in some high‐burden countries to consider antiviral prophylaxis for mothers with lower viremia [30].

Implementation challenges remain, particularly in rural areas where nearly half of deliveries occur outside health facilities [19]. In this study, loss to follow‐up was more frequent in rural participants, reflecting structural barriers such as poor access to healthcare facilities, limited communication infrastructure, and vaccine supply constraints, which were identified in other Ugandan and regional MTCT prevention programs [31, 32]. Addressing these challenges will require targeted investments in community‐based outreach, mobile vaccination services, and health worker training to ensure BD access for home births.

Emerging innovations in vaccine design and delivery may further improve the feasibility of hepatitis B birth dose implementation in settings with substantial barriers to cold‐chain infrastructure and facility‐based delivery. Controlled temperature chain (CTC) approaches allow certain vaccines to be stored and transported outside the traditional +2°C to +8°C cold chain for limited periods, reducing logistical constraints at the point of vaccination [33]. Evidence suggests that CTC strategies can relieve health workers of cold‐chain management burdens, improve efficiency of outreach services, and expand vaccination coverage among underserved populations, particularly in low‐income settings where cold‐chain capacity may be limited or unreliable [33]. Modelling studies of hepatitis B birth dose vaccination have further shown that CTC implementation may be cost‐saving when accounting for reduced disease burden and improved outreach coverage and may be especially impactful in settings where a substantial proportion of deliveries occur outside health care facilities or delivery‐room refrigeration is unavailable [34, 35].

In parallel, next‐generation vaccine delivery technologies may further reduce dependence on traditional supply chains. Microarray patch (MAP) platforms, including dissolving microneedle patches, are currently under development and have demonstrated promising safety and immunogenicity profiles in early studies. Potential advantages include needle‐free administration, reduced need for cold‐chain transport, and the possibility of delivery by minimally trained personnel [36]. Such technologies may offer value in high‐burden settings such as Uganda, where timely BD vaccination is frequently constrained by home births and delayed access to health facilities. As these approaches continue to be evaluated, they may complement existing strategies and further strengthen progress toward the elimination of MTCT of the hepatitis B virus.

Several limitations should be considered. Follow‐up was limited to nine months of age, preventing assessment of chronic infection status beyond infancy. While the 20,000 IU/mL threshold for initiating antiviral therapy is consistent with current WHO recommendations, the occurrence of infections among infants born to mothers with lower viremia suggests that exploring alternative thresholds may be warranted. Additionally, the study population may not fully represent more remote or resource‐limited areas, which could face different implementation challenges and outcomes.

Future investigations should include long‐term follow‐up of exposed infants, evaluate the cost‐effectiveness of expanding antiviral eligibility, and identify practical approaches to ensure timely BD vaccination for infants delivered outside health facilities. Expanding prenatal HBsAg screening to all pregnant women will remain essential to achieving the WHO's 2030 HBV elimination targets.

5. Conclusion

This study provides compelling evidence that integrating targeted maternal antiviral therapy, immediate BD vaccination, and universal infant immunisation into routine maternal and newborn care can reduce HBV MTCT to near‐elimination levels in Uganda. Scaling these interventions nationally could substantially reduce the future burden of chronic HBV infection and its long‐term complications, supporting Uganda's goal of achieving an infant HBV prevalence < 0.1% before 2030.

Author Contributions

H.R., P.O., and J.K. designed the study. P.O., J.K., B.L., V.K., and R.B. conducted the study and had access to the underlying data. S.H. and D.L. drafted the original draft and analysed the data. All authors reviewed and edited the manuscript.

Funding

This work was supported by the John C. Martin Foundation (2022‐G040) and the Ministry of Health, Uganda.

Ethics Statement

This study was conducted following ethical guidelines for human research. All participating mothers provided written informed consent, and confidentiality was maintained throughout. HIV‐positive mothers identified during screening were referred to specialised HIV care centres. Ethical approval was obtained from the Makerere School of Medicine Research Ethics Committee (REC REF 2021–262) and the Uganda National Council for Science and Technology (UNCST; HS2201ES), in accordance with the Declaration of Helsinki.

Conflicts of Interest

The authors declare no conflicts of interest.

Data Availability Statement

The data that support the findings of this study are available from the corresponding author upon reasonable request.