Conference Abstract | Volume 8, Abstract NACNDC/19JASH082 (Poster) | Published: 15 Dec 2025
Moses Ssemwanga1,&, Oliver Angom1, Martin Musumba1, Derrick Kasozi1
1Makerere University, Kampala, Uganda
&Corresponding author: Moses Ssemwanga, Makerere University, Kampala, Uganda, Email: ssemwangamoses5@gmail.com
Received: 22 Sep 2025, Accepted: 20 Oct 2025, Published: 15 Dec 2025
Domain: Infectious Disease Epidemiology
Keywords: Malaria immunity, circumsporozoite protein, HIV-exposed uninfected, pediatric HIV, cotrimoxazole prophylaxis
©Moses Ssemwanga et al. Journal of Interventional Epidemiology and Public Health (ISSN: 2664-2824). This is an Open Access article distributed under the terms of the Creative Commons Attribution International 4.0 License (https://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
Cite this article: Moses Ssemwanga et al., Impaired acquisition of malaria circumsporozoite protein antibodies among HIV-infected and uninfected children under five in Eastern Uganda: Implications for R21 vaccination and integrated control. Journal of Interventional Epidemiology and Public Health. 2025;8(ConfProc6):082. https://doi.org/10.37432/JIEPH-CONFPRO6-00082
The syndemic of HIV and malaria imposes a major dual burden on children in sub-Saharan Africa. With the imminent national rollout of the R21/Matrix-M malaria vaccine in Uganda, which targets the circumsporozoite protein (CSP), characterizing baseline humoral immunity is critical for interpreting vaccine immunogenicity. The impact of pediatric HIV infection, HIV exposure, antiretroviral therapy (ART), and cotrimoxazole prophylaxis on CSP-specific IgG antibodies—a key correlate of protection—remains poorly characterized, constituting a critical evidence gap.
A hospital-based cross-sectional study was conducted (February-June 2025) in five high-transmission districts of Eastern Uganda. We enrolled 206 children aged 1-5 years, comprising 69 HIV-infected, 69 HIV-Exposed Uninfected (HEU), and 68 HIV-Unexposed Uninfected (HUU) controls. Data on demographics and clinical history were collected via questionnaire. CSP-specific IgG titres were quantified using a standardized ELISA against the NF54 CSP antigen, with results reported in ELISA Units (EU)/mL. Statistical analysis included non-parametric comparative tests (Kruskal-Wallis, Mann-Whitney U) and multivariable linear regression adjusted for age, sex, and recent malaria history.
HIV-positive children had significantly lower CSP-specific IgG titres compared to HUU and HEU children. On multivariate analysis, HIV-positive status was independently associated with a 42% reduction in titres (β = -0.42, 95% CI: -0.65, -0.19; p value<0.001). HEU children also exhibited significantly reduced titres compared to the HUU group (β = -0.21, 95% CI: -0.40, -0.02; p=0.03). Cotrimoxazole prophylaxis was associated with blunted antibody acquisition (Users vs. Non-users: β = -0.30, 95% CI: -0.55, -0.05; p=0.02). Conversely, good ART adherence was associated with a 35% increase in CSP titres among HIV-positive children compared to those with poor adherence (β = 0.35, 95% CI: 0.10, 0.60; p=0.007).
HIV infection and exposure significantly impair the natural acquisition of malaria CSP antibodies in children. Cotrimoxazole may further blunt this immune response, while rigorous ART adherence helps restore it. These findings strongly support the prioritization of HIV-affected children in R21 vaccination campaigns and underscore the need to strengthen the integration of malaria prevention strategies into pediatric HIV care programs. A review of cotrimoxazole guidelines for HEU children may be warranted and should be investigated in longitudinal studies.
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