Immunogenicity of seasonal inactivated influenza and inactivated polio vaccines among children in Senegal: Results from a cluster-randomized trial

•Influenza vaccine immunogenicity was assessed as part of a cluster-randomized trial.•Children aged 6 months through 8 years in rural Senegal were enrolled.•Inactivated influenza vaccines were immunogenic in Senegalese children.•Seroconversion rates are higher for older children and with influenza A antigens.•Antigenically naïve children have lower post-vaccine geometric mean titers. Data on influenza vaccine immunogenicity in children are limited from tropical developing countries. We recently reported significant, moderate effectiveness of a trivalent inactivated influenza vaccine (IIV) in a controlled, cluster-randomized trial in children in rural Senegal during 2009, a year of H3N2 vaccine mismatch (NCT00893906). We report immunogenicity of IIV3 and inactivated polio vaccine (IPV) from that trial. We evaluated hemagglutination inhibition (HAI) and polio antibody titers in response to vaccination of three age groups (6 through 35 months, 3 through 5 years, and 6 through 8 years). As all children were IIV naïve, each received two vaccine doses, although titers were assessed after only the first dose for subjects aged 6 through 8 years. Seroconversion rates (4-fold titer rise or increase from