A Randomized Clinical Trial of an Inactivated Avian Influenza A (H7N7) Vaccine |
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Authors: | Robert B Couch Shital M Patel Chianti L Wade-Bowers Diane Ni?o |
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Institution: | 1. Department of Molecular Virology and Microbiology, Baylor College of Medicine, Houston, Texas, United States of America.; 2. Department of Medicine, Baylor College of Medicine, Houston, Texas, United States of America.; Instituto Butantan, Brazil, |
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Abstract: | BackgroundConcern for a pandemic caused by a newly emerged avian influenza A virus has led to clinical trials with candidate vaccines as preparation for such an event. Most trials have involved vaccines for influenza A (H5N1), A (H7N7) or A (H9N2).ObjectiveTo evaluate dosage-related safety and immunogenicity of an inactivated influenza A (H7N7) vaccine in humans.DesignOne hundred twenty-five healthy young adults were randomized to receive two doses intramuscularly of placebo or 7.5, 15, 45 or 90 µg of HA of an inactivated subunit influenza A (H7N7) vaccine (25 per group), four weeks apart. Reactogenicity was evaluated closely for one week and for any adverse effect for six months after each dose. Serum hemagglutination-inhibiting and neutralizing antibody responses were determined four weeks after each dose and at six months.ResultsReactogenicity evaluations indicated the vaccinations were well tolerated. Only one subject developed a ≥4-fold serum hemagglutination-inhibition (HAI) antibody response and a final titer of ≥1∶40 four weeks after dose two and only five subjects developed a neutralizing antibody rise and a final titer of ≥1∶40 in tests performed at a central laboratory. Four of the five were given the 45 or 90 µg HA dosage. A more sensitive HAI assay at the study site revealed a dose-response with increasing HA dosage but only 36% in the 90 µg HA group developed a ≥4-fold rise in antibody in this test and only one of these achieved a titer of ≥1∶32.ConclusionThis inactivated subunit influenza A (H7N7) vaccine was safe but poorly immunogenic in humans.Trials RegistrationClinicalTrials.gov {"type":"clinical-trial","attrs":{"text":"NCT00546585","term_id":"NCT00546585"}}NCT00546585 |
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