To evaluate long-term immunogenicity of a virosomal subunit inactivated influenza vaccine in children with asthma, a prospective study was conducted during 2005-2006 influenza season in six public pediatric clinics in Milan and surroundings, Northern Italy. A single dose (0.5 ml) of a virosomal subunit inactivated influenza vaccine (Inflexal V) was injected in 106 asthmatic children aged 3-9 years. Serum hemagglutinin inhibition antibody titers were determined against the recommended influenza strains A/New Caledonia (H1N1), A/California (H3N2), and B/Shanghai (B), at pre-vaccination and 1 and 6 months after vaccination. Seroconversion rate (95% CI) against the strains A/H1N1, A/H3N2 and B was, respectively, 78% (68.6-85.7), 57% (46.7-66.9) and 66% (55.8-71.2) at 1 month. Seroprotection (titer> or =40) rate for A/H1N1, A/H3N2 and B was, respectively, 87% (77.8-92.2), 82% (72.6-89.7) and 90% (82.6-94.8) at 1 month and 74% (64.3-82.3), 77% (67.5-84.8), and 77% (67.5-84.8) at 6 months. Seroprotection rate was high and persistent (>95%) in children with pre-existing antibodies (titer> or =10) at pre-vaccination for any specific strain. In children without pre-existing antibodies, seroprotection rate for A/H1N1, A/H3N2 and B was, respectively, 67.6%, 66.7% and 74.4% at 1 month, and 35.1%, 56.2% and 41.0% at 6 months after vaccination. Vaccine was well tolerated. These results indicate that in unvaccinated children with asthma vaccination with a single dose of virosomal-adjuvanted influenza vaccine is well tolerated and effective as a whole. However, while immunity response and persistence are excellently high in children with pre-existing antibodies, in children naive for the antigens the immune parameters are lower at 6 months after vaccination.

Long-term immunogenicity of a virosomal subunit inactivated influenza vaccine in children with asthma / G.V. Zuccotti, A. Amendola, A. Viganò, E. Pariani, A. Zappa, L. Pogliani, V. Giacomet, A. Savarino, A. Podestà, A. Rottoli, E. Tanzi, A.R. Zanetti, G. Radaelli. - In: VACCINE. - ISSN 0264-410X. - 25:37-38(2007 Sep 17), pp. 6692-6698. (Intervento presentato al convegno VACCINE Congress tenutosi a Amsterdam nel 2007) [10.1016/j.vaccine.2007.07.013].

Long-term immunogenicity of a virosomal subunit inactivated influenza vaccine in children with asthma

G.V. Zuccotti;A. Amendola;E. Pariani;A. Zappa;V. Giacomet;E. Tanzi;A.R. Zanetti;G. Radaelli
2007

Abstract

To evaluate long-term immunogenicity of a virosomal subunit inactivated influenza vaccine in children with asthma, a prospective study was conducted during 2005-2006 influenza season in six public pediatric clinics in Milan and surroundings, Northern Italy. A single dose (0.5 ml) of a virosomal subunit inactivated influenza vaccine (Inflexal V) was injected in 106 asthmatic children aged 3-9 years. Serum hemagglutinin inhibition antibody titers were determined against the recommended influenza strains A/New Caledonia (H1N1), A/California (H3N2), and B/Shanghai (B), at pre-vaccination and 1 and 6 months after vaccination. Seroconversion rate (95% CI) against the strains A/H1N1, A/H3N2 and B was, respectively, 78% (68.6-85.7), 57% (46.7-66.9) and 66% (55.8-71.2) at 1 month. Seroprotection (titer> or =40) rate for A/H1N1, A/H3N2 and B was, respectively, 87% (77.8-92.2), 82% (72.6-89.7) and 90% (82.6-94.8) at 1 month and 74% (64.3-82.3), 77% (67.5-84.8), and 77% (67.5-84.8) at 6 months. Seroprotection rate was high and persistent (>95%) in children with pre-existing antibodies (titer> or =10) at pre-vaccination for any specific strain. In children without pre-existing antibodies, seroprotection rate for A/H1N1, A/H3N2 and B was, respectively, 67.6%, 66.7% and 74.4% at 1 month, and 35.1%, 56.2% and 41.0% at 6 months after vaccination. Vaccine was well tolerated. These results indicate that in unvaccinated children with asthma vaccination with a single dose of virosomal-adjuvanted influenza vaccine is well tolerated and effective as a whole. However, while immunity response and persistence are excellently high in children with pre-existing antibodies, in children naive for the antigens the immune parameters are lower at 6 months after vaccination.
Asthma ; Children ; Virosomal vaccine
Settore MED/42 - Igiene Generale e Applicata
Settore MED/38 - Pediatria Generale e Specialistica
17-set-2007
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/2434/38063
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