Influenza H1N1 vaccine (split virion, inactivated, adjuvanted) emulsion and suspension for emulsion for injection

Objective: To assess the immunogenicity and safety of the enterovirus 71 vaccine (Vero cell) (EV71 vaccine) and trivalent split-virion influenza vaccine (IIV3). Methods: Healthy infants aged 6–7 months were recruited from Zhejiang Province, Henan Province, and Guizhou Province and randomly assigned to the simultaneous vaccination group, EV71 group, and IIV3 group at a ratio of 1:1:1. Then, 3 mL blood samples were collected before vaccination and 28 days after the second dose of vaccine. Cytopathic effect inhibition assay was used to detect EV71 neutralization antibody, and cytopathic effect inhibition assay was used to detect influenza virus antibody. Results: A total of 378 infants were enrolled and received the first dose of vaccine and were included in the safety analysis, and 350 infants were involved in the immunogenicity analysis. The adverse events rates were 31.75%, 28.57%, and 34.13% in the simultaneous vaccination group, EV71 group, and IIV3 group (p > 0.05), respectively. No vaccine-related serious adverse events were reported. After two doses of EV71 vaccine, the seroconversion rates of EV71 neutralizing antibody were 98.26% and 97.37% in the simultaneous vaccination group and the EV71 group, respectively. After two doses of IIV3, the simultaneous vaccination group and the IIV3 group, respectively, had seroconversion rates of 80.00% and 86.78% for H1N1 antibody, 99.13% and 98.35% for H3N2 antibody, and 76.52% and 80.99% for B antibody. There was no statistically significant difference in the seroconversion rates of influenza virus antibodies between groups (p > 0.05). Conclusions: The coadministration of EV71 vaccine and IIV3 has good safety and immunogenicity in infants aged 6–7 months.

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BACKGROUND: Antineuraminidase antibodies have been identified as a correlate of protection for influenza virus infection. We evaluated the immunogenicity of enhanced influenza vaccines vs standard-dose vaccine in inducing neuraminidase inhibition (NAI) antibodies in older adults in a 2-year randomized trial. METHODS: In 2017-2018, older adults aged 65 to 82 years in Hong Kong were randomly allocated to receive standard-dose quadrivalent (SD-IIV4), high-dose trivalent (HD-IIV3), MF59-adjuvanted trivalent (aIIV3), or recombinant quadrivalent (RIV4) influenza vaccines of 2017-2018 northern hemisphere formations; HD-IIV3, aIIV3, and RIV4 are enhanced vaccines. NAI antibodies to the 2017-2018 A(H1N1)pdm09 and A(H3N2) vaccine strains were determined from 400 recipients (100 per vaccine group). In 2018-2019, participants were rerandomized to receive the same or a different type of vaccine of northern hemisphere formations. NAI antibodies to the 2018-2019 A(H1N1)pdm09 and A(H3N2) vaccine strains were determined from SD-IIV4 (n = 45), HD-IIV3 (n = 64), aIIV3 (n = 75), or RIV4 (n = 29) recipients. NAI antibody titers on the day of vaccination and 30 days postvaccination were used to compare the geometric mean fold rise (GMFR) of titers and the seroconversion rates of enhanced influenza vaccines vs SD-IIV4. RESULTS: SD-IIV4, HD-IIV3, and aIIV3 induced detectable NAI antibodies to N1 and N2 antigens with GMFR significantly greater than 1. In both years, aIIV3 induced significantly higher GMFR and seroconversion rates to N1 and N2 antigens than SD-IIV4. Notably, individual baseline NAI antibody titers were inversely associated with the postvaccination antibody titer fold rises in all vaccine groups. CONCLUSIONS: MF-59-adjuvanted aIIV3 induced a superior NAI antibody response in older adults than SD-IIV4 in a 2-year randomized trial. CLINICAL TRIALS REGISTRATION: ClinicalTrials.gov: NCT03330132.

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