Persistence of Antibodies at Three, Four and Five Years of Age to Ten-valent Pneumococcal Polysaccharide Protein D-conjugate Vaccine in South African Children According to HIV Status

BACKGROUND: Streptococcus pneumoniae remains a major cause of bacterial disease in young children, with increased risk and morbidity in children exposed to HIV but uninfected (CEHU) and children living with HIV (CLWH). This study assessed the persistence of vaccine-specific antibodies, opsonophagocytic activity (OPA) and nasopharyngeal carriage of S. pneumoniae and Haemophilus influenzae in HIV-unexposed children, CEHU and CLWH. METHODS: HIV-unexposed children, CEHU and CLWH who initially received a 10-valent pneumococcal polysaccharide protein D-conjugate vaccine 3-dose primary schedule at 6, 10 and 14 weeks with a booster at 9 months (3 + 1) were followed up at 3, 4 and 5 years to measure serum IgG concentrations, OPA and nasopharyngeal colonization. Geometric mean concentrations (GMCs) and titers, along with the prevalence of colonization, are reported for each group. RESULTS: Compared with HIV-unexposed children, CLWH had similar antibody concentrations for all serotypes at each timepoint except at 4 years where GMCs were lower for 6B and at 5 years where GMCs were lower for 6A. OPA titers were lower for 6B at 3 years and lower for 4B at 4 and 5 years in CLWH compared with HIV-unexposed children. Comparing CEHU to HIV-unexposed children, both study groups had similar GMCs and OPA titers for all serotypes during the study period. Prevalence of nasopharyngeal colonization of S. pneumoniae and H. influenzae was similar amongst the 3 study groups. CONCLUSIONS: There was no association between HIV exposure or infection and antibody persistence or colonization at 3, 4 and 5 years of age.