RESUMO
The study evaluated the immunogenicity and efficacy of a trivalent subunit MF59-adjuvanted influenza vaccine (A/Wisconsin/67/05 (H3N2), A/Solomon Islands/3/06 (H1N1) and B/Malaysia/2506/04) in preventing serologically diagnosed infections in a group of 67 institutionalized elderly volunteers during 2007/2008 winter, characterized by co-circulation of drifted A/H3N2, A/H1N1 and B influenza viruses. Influenza vaccination induced a significant increase in the amounts of hemagglutination inhibiting antibodies, both against the vaccine and the epidemic drifted strains. However, vaccination did not prevent the circulation of the new drifted influenza B virus (B/Florida/4/06-like), belonging to the B/Yamagata/16/88-lineage, antigenically and genetically distinct from B/Victoria/2/87-lineage viruses from which the vaccine B strain was derived.
Assuntos
Surtos de Doenças/prevenção & controle , Vacinas contra Influenza/administração & dosagem , Influenza Humana/epidemiologia , Casas de Saúde , Adjuvantes Imunológicos/administração & dosagem , Idoso , Idoso de 80 Anos ou mais , Anticorpos Antivirais/sangue , Antígenos Virais/genética , Feminino , Testes de Inibição da Hemaglutinação , Humanos , Imunização , Vírus da Influenza A Subtipo H1N1/classificação , Vírus da Influenza A Subtipo H1N1/genética , Vírus da Influenza A Subtipo H3N2/classificação , Vírus da Influenza A Subtipo H3N2/genética , Vírus da Influenza B/classificação , Vírus da Influenza B/genética , Influenza Humana/imunologia , Influenza Humana/prevenção & controle , Itália/epidemiologia , Pessoa de Meia-Idade , Filogenia , Polissorbatos/administração & dosagem , Esqualeno/administração & dosagemRESUMO
This study examined the antibody response against the three vaccine antigens and the epidemic A/H3N2 drift variant (A/California) and the prevention of laboratory diagnosed influenza infections in a group of elderly institutionalized people vaccinated with the 2004/2005 influenza vaccine. Antibody titres were measured by hemagglutination inhibition (HI) in sera collected before and 1 month after vaccination. Laboratory diagnosis was done examining throat swabs (RT-PCR or MDCK cell culture) or by serology (seroconversion comparing HI titres in sera collected 1 and 5 months after vaccination). Results obtained showed that influenza vaccination induced an adequate immune response against the three vaccine antigens and the epidemic A/H3N2 variant, however it was not capable of preventing an influenza outbreak due to the new A/H3N2 (A/California) variant.