Hepatitis B virus infection and vaccine coverage among children living with HIV, HIV-exposed uninfected, and HIV-unexposed uninfected children in the Western Cape, South Africa

Collins, Courteney Jade

Hepatitis B virus infection and vaccine coverage among children living with HIV, HIV-exposed uninfected, and HIV-unexposed uninfected children in the Western Cape, South Africa

Thesis / Dissertation

2026

Publisher

University of Cape Town

Department

Department of Public Health and Family Medicine

Faculty

Faculty of Health Sciences

Abstract

Introduction: Limited evidence on the burden of hepatitis B virus (HBV) infection among children living with HIV (CLWH), HIV-exposed uninfected (HEU) and HIV-unexposed uninfected (HUU) children hinders progress towards eliminating hepatitis B as a public health threat in South Africa. Methods: This study used secondary data and archived sera (N= 671) obtained from children <13 years old presenting at health facilities in the Western Cape, South Africa. Hepatitis B vaccine coverage was assessed using vaccination records for doses 1 to 3 by 12 months of age. Timely uptake of the hepatitis B vaccine was calculated as the difference between the actual and expected date of vaccine receipt, defined as 4 days before and up to 28 days after the recommended age. The prevalence of HBV infection was determined based on the presence of HBsAg within each subgroup. Logistic regression analysis was performed to assess factors influencing incomplete and delayed vaccination. Results: Coverage with all three doses by 12 months of age was 86.7% (13/15), 77.0% (57/74), and 80.9% (263/325) for CLWH, HEU, and HUU, respectively (p=0.645). Hepatitis B vaccine coverage decreased across all subgroups as the dosing schedule progressed from doses 1 to 3. Across the strata, the highest proportion of participants with delayed uptake for the third dose of hepatitis B vaccine was noted among CLWH at 23.1% (3/13), followed by 21.6% (58/269) among HUU and 15.3% (9/59) among HEU children (p= 0.540). The median delay in vaccination for dose 3 was highest among CLWH (11.3 weeks) compared to HUU (6.7 weeks) (p= 0.368). HBV infection was detected in 1.4% (1/74) of HEU and 0.3% (1/328) of HUU children, while no cases were observed among CLWH. Factors associated with completing the three-dose hepatitis B vaccine series included crèche attendance, low-to-middle socio-economic status (SES), timely uptake of dose 1, participant's age (in months), and HIV exposure status. For the third dose, crèche attendance reduced the likelihood of delayed uptake by 69%, while a monthly increase in the participant's age was associated with a 2% increase in delayed uptake in the multivariable model. Conclusion: Our findings highlight disparities in timely hepatitis B vaccine uptake and coverage, emphasizing the need for targeted interventions ensuring timely vaccine uptake among HIV- exposed children.