Safety and immunogenicity of an 8 year interval heterologous prime-boost influenza A/H7N7-H7N9 vaccination

• Published in: Vaccine Vol. 37; no. 19; pp. 2561 - 2568
• Main Authors: El Sahly, Hana M., Atmar, Robert L., Patel, Shital M., Bellamy, Abbie, Liu, Liwei, Hong, Wenshan, Zhu, Huachen, Guan, Yi, Keitel, Wendy A.
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier Ltd 01.05.2019; Elsevier Limited
• Subjects: Adult; Antibodies; Antibodies, Neutralizing; Antibodies, Viral; Antibody response; Antigenic drift; Antigens; Avian; Avian flu; Female; Hemagglutination inhibition; Hemagglutination Inhibition Tests; Hemagglutinins; Homology; Humans; Immunization; Immunization, Secondary; Immunogenicity; Immunogenicity, Vaccine; Influenza; Influenza A; Influenza A Virus, H7N7 Subtype - immunology; Influenza A Virus, H7N9 Subtype - immunology; Influenza A/H7N9; Influenza Vaccines - administration & dosage; Influenza Vaccines - adverse effects; Influenza Vaccines - immunology; Influenza, Human - prevention & control; Male; Middle Aged; Optimization; Pandemic; Pandemics; Patient Outcome Assessment; Prime-boost; Priming; Vaccination; Vaccines; Viruses; Workflow; Netherlands; Influenza A/H7N9; Pandemic; Avian; Prime-boost; Vaccines; Influenza
• ISSN: 0264-410X; 1873-2518
• DOI: 10.1016/j.vaccine.2019.03.071

•Inactivated influenza A/H7N7 vaccine results in development of memory responses.•Cross-reactive antibodies develop post heterologous influenza A/H7 prime-boost.•The inclusion of an AS03 adjuvant results in broadly cross-reactive antibodies. Influenza A/H7N9 viruses are undergoing antigenic drift since their emergence in 2013, and vaccination strategies are needed for pandemic preparedness. Two doses of adjuvanted monovalent inactivated influenza A/H7N9 vaccine (IIV1 A/H7N9) are needed for optimal serological responses. However, administering 2 doses in a pandemic setting might be challenging. We evaluated the immunogenicity of “boosting” with IIV1 A/H7N9 in subjects “primed” 8 years previously with IIV1 A/H7N7. We administered 1 booster dose containing 45 mcg of IIV1 A/H7N9 hemagglutinin to 17 recipients of 2 prior doses of IIV1 A/H7N7, and to 10 influenza A/H7-naïve subjects. We tested their post-boosting sera for antibodies (Ab) against homologous influenza A/H7N9 using a hemagglutination inhibition assay; and compared their Ab titers to those in stored sera from recipients of AS03-adjuvanted IIV1 A/H7N9 against 9 strains of influenza A/H7N9 viruses. The percentage of subjects with Ab titers ≥40 on Days 9 and 29 post boosting, respectively, was 65% and 41% in primed subjects and 10% and 0% in unprimed subjects. The Ab titers in recipients of AS03-adjuvanted IIV1 A/H7N9 were higher than those in the prime-boost group against a panel of influenza A/H7N9 viruses, except for 2 highly pathogenic strains. Priming with IIV1 A/H7 results in serological responses following a delayed boost with 1 dose of unadjuvanted IIV1 A/H7N9, despite lack of antibody response after the prime. Optimizing prime-boost approaches would benefit pandemic preparedness. ClinicalTrials.gov identifier: NCT02586792.