Immunogenicity of seasonal inactivated influenza and inactivated polio vaccines among children in Senegal: Results from a cluster-randomized trial. Issue 47 (3rd November 2020)

• Record Type: Journal Article
• Authors: Niang, Mbayame; Deming, Meagan E.; Goudiaby, Deborah; Diop, Ousmane M.; Dia, Ndongo; Diallo, Aldiouma; Ortiz, Justin R.; Diop, Doudou; Lewis, Kristen D.C.; Lafond, Kathryn E.; Widdowson, Marc-Alain; Victor, John C.; Neuzil, Kathleen M.
• Is Part Of: Vaccine. Volume 38:Issue 47(2020)
• Page Start: 7526
• Page End: 7532
• Publication Date: 2020-11-03
• Subjects: Human influenza -- Influenza vaccine -- Immunogenicity -- Randomized controlled trial -- Children; CDC United States Centers for Disease Control and Prevention -- FDA United States Food and Drug Administration -- HAI hemagglutination inhibition -- HDSS Health and Demographic Surveillance System -- IIV3 trivalent inactivated influenza vaccine -- IPV inactivated poliovirus vaccine -- P1 poliovirus type 1 -- P2 poliovirus type 2 -- P3 poliovirus type 3 -- TCID50 tissue culture infective dose -- WHO World Health Organization; Vaccines -- Periodicals; 615.372
• DOI: 10.1016/j.vaccine.2020.09.059
• Languages: English
• ISSNs: 0264-410X

Abstract

Highlights: 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. Abstract: 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 <1:10 to ≥1:40) were 74–87% for A/H1N1, 76–87% for A/H3N2, and 54–79% for B/Yamagata. Seroprotection rates (HAI titer ≥ 1:40) were 79–88% for A/H1N1, 88–96% for A/H3N2, and 52–74% for B/Yamagata. IIV responses were lowest in the youngest age group, and they were comparable between ages 3 through 5 years after two doses and 6 through 8 years after one dose. We found that baseline seropositivity (HAI titer ≥ 1:10) was an effect modifier of IIV response. Using a seroprotective titer (HAI titer ≥ 1:160) recommended for IIV evaluation in children, we found that among subjects who were seropositive at baseline, 69% achieved seroprotection for both A/H1N1 and A/H3N2, while among those who were seronegative at baseline, seroprotection was achieved in 11% for A/H1N1 and 22% for A/H3N2. The IPV group had high baseline polio antibody seropositivity and appropriate responses to vaccination. Our data emphasize the importance of a two-dose IIV3 series in vaccine naïve children. IIV and IPV vaccines were immunogenic in Senegalese children.