Safety and immunogenicity of unadjuvanted subvirion monovalent inactivated influenza H3N2 variant (H3N2v) vaccine in children and adolescents.

Document Type

Article

Publication Date

8-23-2019

Identifier

DOI: 10.1016/j.vaccine.2019.07.085

Abstract

OBJECTIVE: In response to the emergence of influenza viruses with pandemic potential, we evaluated a swine-origin influenza A/H3N2 variant (H3N2v) vaccine in children.

STUDY DESIGN: This multicenter phase II open-label study assessed the safety and immunogenicity of two doses, 21 days apart, of investigational unadjuvanted subvirion monovalent inactivated H3N2v vaccine administered via intramuscular injection. Children 6-35 months of age received 7.5mcg or 15mcg of hemagglutinin (HA)/dose; children 3-17 years of age received 15mcg HA/dose. Safety and reactogenicity were assessed by measuring the occurrence of solicited injection site and systemic reactions in the 7 days after each vaccination; adverse events were assessed for 42 days and serious adverse events for 7 months after the first vaccination. Immunogenicity was evaluated by measuring hemagglutination inhibition (HAI) and neutralizing (Neut) antibodies to H3N2v prior to and 21 days after each vaccination. Cross-reactivity against seasonal H3N2 strains was evaluated.

RESULTS: The H3N2v vaccine was well tolerated. Transient mild to moderate injection site tenderness, pain and erythema was observed, with the most commonly reported systemic reactogenicity being irritability in children 6-35 months, and headache and fatigue in children 9-17 years old. Children 6-35 months old, whether they received 7.5mcg or 15mcg/dose, had low HAI and Neut antibody responses after two doses compared to older children. Children under 9 years of age required two doses of vaccine to demonstrate a response, while 9-17 year olds responded well after one dose. Previous influenza vaccination and older age were associated with higher immune responses to H3N2v vaccine. Children 9-17 years of age also developed cross-reactive antibodies against recent seasonal H3N2 influenza viruses.

CONCLUSION: The H3N2v vaccine was safe and immunogenic in children and adolescents. Age-related increases in immunogenicity against H3N2v and seasonal H3N2 viruses were observed, suggesting prior priming via infection and/or immunization. Clinical trial registry: The trial is registered with clinicaltrial.gov: NCT02100436.

Journal Title

Vaccine

Volume

37

Issue

36

First Page

5161

Last Page

5170

MeSH Keywords

Adolescent; Adult; Antibodies, Viral; Child; Child, Preschool; Female; Hemagglutination Inhibition Tests; Humans; Influenza A Virus, H3N2 Subtype; Influenza Vaccines; Influenza, Human; Male; Vaccines, Inactivated; Young Adult

Keywords

Adolescents; Children; Cross-reactive antibodies; H3N2 variant; Immunogenicity; Influenza; Safety

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