Project Details

Malaria and measles vaccine response in Kenyan infants treated for iron deficiency anemia

Nicole Stoffel, PhD

Summary

BACKGROUND: Malaria remains a leading cause of childhood morbidity and mortality in sub-Saharan Africa, while iron deficiency anemia (IDA) affects over half of infants in this region and may impair adaptive immunity. Moderate efficacy of current malaria vaccines has been observed, and both animal and human studies support that IDA can weaken vaccine responses. GAP: Despite the prevalence of IDA and its impact on immune function, it is unknown whether treating IDA at the time of malaria vaccination—including with newer vaccines like R21/Matrix- M — can improve vaccine-induced immunity and improve vaccine efficacy in African infants. HYPOTHESIS: Treating IDA in Kenyan infants at the time of malaria vaccination with the R21/Matrix-M vaccine will lead to stronger immune responses, specifically higher levels of anti-circumsporozoite protein (CSP) IgG antibodies and improved cellular immunity, compared to untreated infants with IDA. METHODS: This double-blind, randomized controlled trial will enroll 288 infants with IDA at six months of age in rural Kenya and allocate them to receive either daily iron plus multivitamin syrup or multivitamin only, alongside the WHO-recommended schedule of the R21/Matrix-M malaria vaccine. Immunological endpoints, including antibody titers and T/B cell profiles, will be measured throughout the study, with close monitoring and follow-up. RESULTS: Pending. IMPACT: If we can demonstrate that the response to malaria vaccines is improved by iron, this would provide strong support for early detection and correction of IDA in infancy at the time of vaccination. Given the high prevalence of anemia in African infants and the substantial burden of malaria, even a modest reduction in vaccine immunogenicity due to IDA could mean that its prevention would have significant public health benefits.