Native IAV H3N2 (A/Wisconsin/67/05) Antigen

Background: Influenza B (Yamagata/Victoria lineage) can cause severe forms of respiratory infection among the pediatric population as welt as influenza A strains (H3N2/H1N1). Vaccination against all four strains is required to prevent infection and severe outcome. This study is the first study to assess the immunogenicity of Quadrivalent Influenza HA vaccine (QIV) and ascertain safety among children in Indonesia. Methods: This is an open labeled, single arm, bridging clinical study involving unprimed healthy children 6-35 months of age (Group I) and 3-8 years of age (Group II). Subjects on both groups receiving two doses of QIV with a 28 days interval. Serology tests were performed on baseline and 28 days post-vaccination. Hemagglutination inhibition antibody titers were analyzed for Geometric Mean Titer (GMT), seroprotection, and seroconversion rates. Solicited reactions, unsolicited adverse events, and serious adverse events were observed up to 28 days post-vaccination. Results: Out of 270 subjects enrolled, 269 subjects completed the study. Immunogenicity analysis were evaluated on 254 subjects. Seroprotection rates were >= 85% for all vaccine strains in both groups. Seroconversion of more than 4 folds for all strains occurred in both groups post-vaccination. In Group I, the increase of GMT for A/H1N1, A/H3N2, B/Texas, and B/Phuket was 12.5, 14.5, 8.2, and 6.4 folds, respectively. In Group II the increase of GMT for A/HIN1, A/H3N2, B/Texas, and B/Phuket was 14, 17, 10, and 8 folds, respectively. The majority of local adverse events (AEs) after the first and second immunizations were immediate injection-site pain (10.4% and 12.6%). The majority of systemic AEs after the first and second immunizations were delayed unsolicited AEs (14.8% and 14.9%). No vaccine-related serious adverse events or deaths were reported. Conclusion: The investigational QIV was immunogenic with an acceptable safety profile in children 6 months to 8 years of age. (C) 2019 The Author(s). Published by Elsevier Ltd.

Background: New jurisdictionally-based vaccination programs were established providing free quadrivalent influenza vaccine (QIV) for preschool Australian children in 2018. This was in addition to the National Immunisation Program (NIP) funded QIV for Indigenous children and children with comorbid medical conditions. We assessed the impact of this policy change on influenza disease burden and vaccine coverage, as well as report on 2018 vaccine effectiveness in a hospital-based surveillance system. Methods: Subjects were recruited prospectively from twelve PAEDS-FluCAN sentinel hospital sites (April until October 2018). Children aged <= 16 years hospitalised with an acute respiratory illness (ARI) and laboratory-confirmed influenza were considered cases. Hospitalised children with ARI who tested negative for influenza were considered controls. VE estimates were calculated from the adjusted odds ratio of vaccination in cases and controls. Results: A total of 458 children were hospitalised with influenza: 31.7% were <2 years, 5.0% were Indigenous, and 40.6% had medical comorbidities predisposing to severe influenza. Influenza A was detected in 90.6% of children (A/H1N1: 38.0%; A/H3N2: 3.1%; A/unsubtyped 48.6%). The median length of stay was 2 days (IQR: 1,3) and 8.1% were admitted to ICU. Oseltamivir use was infrequent (16.6%). Two in-hospital deaths occurred (0.45%). 12.0% of influenza cases were vaccinated compared with 36.0% of test-negative controls. Vaccine effectiveness of QIV for preventing influenza hospitalisation was estimated at 78.8% (95%CI: 66.9; 86.4). Conclusions: Compared with 2017 (n = 1268 cases), a significant reduction in severe influenza was observed in Australian children, possibly contributed to by improved vaccine coverage and high vaccine effectiveness. Despite introduction of jurisdictionally-funded preschool programs and NIP-funded vaccine for children with risk factors for severe disease, improved coverage is required to ensure adequate protection against paediatric influenza morbidity and mortality. (C) 2020 Elsevier Ltd. All rights reserved.