Antibody persistence in mothers one year after pneumococcal immunization in pregnancy

► Pregnant women were randomized to receive pneumococcal polysaccharide vaccine or control. ► We followed IgG antibody geometric mean concentrations (GMCs) for 12 months. ► GMCs remained stable for 12 months in pneumococcal vaccinees. ► GMCs increased significantly in control group women, likely due to infant exposure.