This is a Phase 1, randomized, controlled, dose-ranging clinical trial to assess the safety and immunogenicity of novel influenza A Group 1 and influenza A Group 2 mRNA chimeric hemagglutinin (HA) vaccine candidates given as intramuscular injections alone and in combination. A total of 60 healthy men and non-pregnant, non-breastfeeding women aged 18 through 59 years will be enrolled in one of 6 study arms. The 6 arms will consist of: 1) Sequential influenza A Group 1 mRNA chimeric hemagglutinin: cH8/1 (25 µg) followed by cH5/1 (25 µg), 2) Sequential influenza A Group 2 mRNA chimeric hemagglutinin: cH15/3 (25 µg) followed by cH4/3 (25 µg), 3) Sequential combined influenza A Group 1 and Group 2 mRNA chimeric hemagglutinin: cH8/1 + cH15/3 (25 µg) followed by cH5/1 + cH4/3 (25 µg), 4) A single dose of combined influenza A Group 1 and Group 2 mRNA chimeric hemagglutinin: cH8/1 + cH15/3 (50 µg) followed by placebo, 5) A single dose of combined influenza A Group 1 and Group 2 mRNA chimeric hemagglutinin: cH5/1 + cH4/3 (50 µg) followed by placebo, 6) Sequential combined influenza A Group 1 and Group 2 mRNA chimeric hemagglutinin: cH8/1 + cH15/3 (50 µg) followed by cH5/1 + cH4/3 (50 µg). The primary objectives are to evaluate safety and immunogenicity: 1) To assess the safety and reactogenicity of one or two doses of monovalent or bivalent Group 1 and 2 study products and 2) To describe the Group 1 and 2 anti-HA stalk IgG antibody responses of one or two doses of monovalent or bivalent Group 1 and 2 study products by ELISA.
Age range
18 Years – 59 Years
Sex
ALL
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Geometric mean fold rise (GMFR) from baseline in HA-stalk specific titers by ELISA
Timeframe: Day 1 through Day 85
Geometric mean titer (GMT) by ELISA
Timeframe: Day 1 Through Day 85
Number and percentage of participants with greater than or equal to a 2-, 4-, and 10-fold rise from baseline in Hemagglutinin (HA)-stalk specific titers by ELISA
Timeframe: Day1 through Day 85
Occurrence of Adverse Events of Special Interest (AESIs)
Timeframe: Day 1 through Day 240
Occurrence of Guillain-Barre Syndrome (GBS)
Timeframe: Through Day 240
Occurrence of hematological or biochemical laboratory adverse events
Timeframe: Day 8 through Day 64
Occurrence of laboratory confirmed influenza A infection
Timeframe: Through Day 240
Occurrence of Medically-Attended Adverse Events (MAAEs)
Timeframe: Through Day 240
Occurrence of New-Onset Chronic Medical Conditions (NOCMCs)
Timeframe: Through Day 240
Occurrence of Serious Adverse Events (SAEs)
Timeframe: Through Day 240
Occurrence of solicited local adverse events (AEs)
Timeframe: Day 1 through Day 64
Occurrence of solicited systemic adverse events (AEs)
Timeframe: Day 1 through Day 64
Occurrence of unsolicited adverse events (AEs)
Timeframe: Day 1 through Day 85