RESUMO
In Egypt, efforts to control highly pathogenic H5N1 avian influenza virus in poultry and in humans have failed despite increased biosecurity, quarantine, and vaccination at poultry farms. The ongoing circulation of HP H5N1 avian influenza in Egypt has caused >100 human infections and remains an unresolved threat to veterinary and public health. Here, we describe that the failure of commercially available H5 poultry vaccines in Egypt may be caused in part by the passive transfer of maternal H5N1 antibodies to chicks, inhibiting their immune response to vaccination. We propose that the induction of a protective immune response to H5N1 is suppressed for an extended period in young chickens. This issue, among others, must be resolved and additional steps must be taken before the outbreaks in Egypt can be controlled.
Assuntos
Virus da Influenza A Subtipo H5N1/imunologia , Virus da Influenza A Subtipo H5N1/patogenicidade , Vacinas contra Influenza/farmacologia , Influenza Aviária/prevenção & controle , Doenças das Aves Domésticas/prevenção & controle , Criação de Animais Domésticos , Animais , Animais Recém-Nascidos , Anticorpos Antivirais/sangue , Galinhas , Reações Cruzadas , Surtos de Doenças/prevenção & controle , Surtos de Doenças/veterinária , Egito/epidemiologia , Feminino , Humanos , Imunização Passiva , Influenza Aviária/epidemiologia , Influenza Aviária/imunologia , Influenza Aviária/transmissão , Influenza Humana/epidemiologia , Influenza Humana/imunologia , Influenza Humana/prevenção & controle , Influenza Humana/transmissão , Masculino , Doenças das Aves Domésticas/imunologia , Doenças das Aves Domésticas/transmissão , Saco Vitelino/imunologiaRESUMO
Levels of preexisting antibodies to the hemagglutinin of pandemic influenza A(H1N1) 2009 (hereafter pandemic H1N1) virus positively correlate with age. The impact of contemporary seasonal influenza vaccines on establishing immunity to other pandemic H1N1 proteins is unknown. We measured serum antibodies to the neuraminidase (NA) of pandemic H1N1 in adults prior to and after vaccination with seasonal trivalent inactivated influenza vaccines. Serum antibodies to pandemic H1N1 NA were observed in all age groups; however, vaccination elevated levels of pandemic H1N1 NA antibodies predominately in elderly individuals (age, ⩾60 years). Therefore, contemporary seasonal vaccines likely contribute to reduction of pandemic H1N1-associated disease in older individuals.