title: Antibody Persistence in Adults Two Years after Vaccination with an H1N1 2009 Pandemic Influenza Virus-Like Particle Vaccine.
abstract: The influenza virus is a human pathogen that causes epidemics every year, as well as potential pandemic outbreaks, as occurred in 2009. Vaccination has proven to be sufficient in the prevention and containment of viral spreading. In addition to the current egg-based vaccines, new and promising vaccine platforms, such as cell culture-derived vaccines that include virus-like particles (VLPs), have been developed. VLPs have been shown to be both safe and immunogenic against influenza infections. Although antibody persistence has been studied in traditional egg-based influenza vaccines, studies on antibody response durations induced by VLP influenza vaccines in humans are scarce. Here, we show that subjects vaccinated with an insect cell-derived VLP vaccine, in the midst of the 2009 H1N1 influenza pandemic outbreak in Mexico City, showed antibody persistence up to 24 months post-vaccination. Additionally, we found that subjects that reported being revaccinated with a subsequent inactivated influenza virus vaccine showed higher antibody titres to the pandemic influenza virus than those who were not revaccinated. These findings provide insights into the duration of the antibody responses elicited by an insect cell-derived pandemic influenza VLP vaccine and the possible effects of subsequent influenza vaccination on antibody persistence induced by this VLP vaccine in humans.
authors.affiliation: Medical Research Unit on Immunochemistry, Specialties Hospital, National Medical Centre "Siglo XXI", Mexican Social Security Institute, Mexico City, D.F., Mexico.|Departamento de Inmunología, Escuela Nacional de Ciencias Biológicas, Instituto Politécnico Nacional, México, D.F., México.
authors.forename: Nuriban
authors.initials: N
authors.lastname: Valero-Pacheco
authors.affiliation: Medical Research Unit on Immunochemistry, Specialties Hospital, National Medical Centre "Siglo XXI", Mexican Social Security Institute, Mexico City, D.F., Mexico.|Departamento de Inmunología, Escuela Nacional de Ciencias Biológicas, Instituto Politécnico Nacional, México, D.F., México.
authors.forename: Marisol
authors.initials: M
authors.lastname: Pérez-Toledo
authors.affiliation: Unidad de Investigación en Epidemiología Clínica, Hospital de Pediatría, Centro Médico Nacional "Siglo XXI",  Instituto Mexicano del Seguro Social, México, D.F., México.
authors.forename: Miguel Ángel
authors.initials: MÁ
authors.lastname: Villasís-Keever
authors.affiliation: Medical Research Unit on Immunochemistry, Specialties Hospital, National Medical Centre "Siglo XXI", Mexican Social Security Institute, Mexico City, D.F., Mexico.
authors.forename: Adriana
authors.initials: A
authors.lastname: Núñez-Valencia
authors.affiliation: Medical Research Unit on Immunochemistry, Specialties Hospital, National Medical Centre "Siglo XXI", Mexican Social Security Institute, Mexico City, D.F., Mexico.
authors.forename: Ilka
authors.initials: I
authors.lastname: Boscó-Gárate
authors.affiliation: Departamento de Investigación y Desarrollo, Laboratorio Avi-Mex, S.A. de C.V., México, D.F., México.
authors.forename: Bernardo
authors.initials: B
authors.lastname: Lozano-Dubernard
authors.affiliation: Departamento de Investigación y Desarrollo, Laboratorio Avi-Mex, S.A. de C.V., México, D.F., México.
authors.forename: Horacio
authors.initials: H
authors.lastname: Lara-Puente
authors.affiliation: Departamento de Inmunología, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, México, D.F., México.
authors.forename: Clara
authors.initials: C
authors.lastname: Espitia
authors.affiliation: Instituto Nacional de Salud Pública, Cuernavaca, Morelos, México.
authors.forename: Celia
authors.initials: C
authors.lastname: Alpuche-Aranda
authors.affiliation: Medical Research Unit on Immunochemistry, Specialties Hospital, National Medical Centre "Siglo XXI", Mexican Social Security Institute, Mexico City, D.F., Mexico.
authors.forename: Laura C
authors.initials: LC
authors.lastname: Bonifaz
authors.affiliation: Medical Research Unit on Immunochemistry, Specialties Hospital, National Medical Centre "Siglo XXI", Mexican Social Security Institute, Mexico City, D.F., Mexico.
authors.forename: Lourdes
authors.initials: L
authors.lastname: Arriaga-Pizano
authors.affiliation: Facultad de Química, Universidad Nacional Autónoma de México, México, D.F., México.
authors.forename: Rodolfo
authors.initials: R
authors.lastname: Pastelin-Palacios
authors.affiliation: Medical Research Unit on Immunochemistry, Specialties Hospital, National Medical Centre "Siglo XXI", Mexican Social Security Institute, Mexico City, D.F., Mexico.
authors.forename: Armando
authors.initials: A
authors.lastname: Isibasi
authors.affiliation: Medical Research Unit on Immunochemistry, Specialties Hospital, National Medical Centre "Siglo XXI", Mexican Social Security Institute, Mexico City, D.F., Mexico.|Nuffield Department of Medicine, University of Oxford, Oxford, United Kingdom.
authors.forename: Constantino
authors.initials: C
authors.lastname: López-Macías
mesh_terms: D000328:Adult; D000368:Aged; D000914:Antibodies, Viral / Q000097:blood*; D003430:Cross-Sectional Studies; D004311:Double-Blind Method; D005260:Female; D006801:Humans; D007117:Immunization, Secondary; D053118:Influenza A Virus, H1N1 Subtype / Q000276:immunology*; D007252:Influenza Vaccines / Q000276:immunology*; D007251:Influenza, Human / Q000453:epidemiology / Q000821:virology; D008297:Male; D008800:Mexico / Q000453:epidemiology; D008875:Middle Aged; D058873:Pandemics; D016036:Seroepidemiologic Studies; D013997:Time Factors; D014611:Vaccination; D015164:Vaccines, Inactivated; D058425:Vaccines, Virus-Like Particle / Q000276:immunology*; D055815:Young Adult
chemical_list: D000914:Antibodies, Viral; D007252:Influenza Vaccines; D015164:Vaccines, Inactivated; D058425:Vaccines, Virus-Like Particle