Vaccine
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Comparative Study
Pandemic H1N1 vaccine requires the use of an adjuvant to protect against challenge in naïve ferrets.
In the context of an A/H1N1 influenza pandemic situation, this study demonstrates that heterologous vaccination with an AS03-adjuvanted 2008/2009 seasonal trivalent and pandemic H5N1 monovalent split vaccine conferred partial protection in influenza-naïve ferrets after challenge with the influenza pandemic H1N1 A/The Netherlands/602/09 virus. Further, unlike saline control and non-adjuvanted vaccine, it was shown that immunization of naïve ferrets with an AS03-adjuvanted pandemic H1N1 A/California/7/09 influenza split vaccine induced increased antibody response and enhanced protection against the challenge strain, including significant reduction in viral shedding in the upper respiratory tract and reduced lung pathology post-challenge. These results show the need for vaccination with the adjuvanted vaccine to fully protect against viral replication and influenza disease in unprimed ferrets.
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Comparative Study
Protective anti-Pseudomonas aeruginosa humoral and cellular mucosal immunity by AdC7-mediated expression of the P. aeruginosa protein OprF.
Replication-deficient adenoviral (Ad) vectors are an attractive platform for a vaccine against lung infections caused by Pseudomonas aeruginosa. Ad vectors based on non-human serotypes have been developed to circumvent the problem of pre-existing anti-Ad immunity in humans. The present study analyzes the anti-P. aeruginosa systemic and lung mucosal immunity elicited by a non-human primate-based AdC7 vector expressing the outer membrane protein F (AdC7OprF) of P. aeruginosa. ⋯ In contrast, OprF-specific INF-γ responses in lung T cells stimulated with either spleen or lung DC were increased following immunization with AdC7OprF compared to Ad5OprF (p<0.05). Interestingly, direct administration of AdC7OprF to the respiratory tract resulted in an increase of OprF-specific IgG in serum, OprF-specific IgG and IgA in lung ELF, and OprF-specific INF-γ in lung T-cells compared to immunization with Ad5OprF, and survival following challenge with a lethal dose of P. aeruginosa. These data demonstrate that systemic or lung mucosal immunization with an AdC7-based vaccine vector induces superior pulmonary humoral and cellular anti-transgene immunity compared to immunization with an Ad5-based vector and favors AdC7-based vectors as vaccines to induce lung mucosal immunity.
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Randomized Controlled Trial
A nasally administered trivalent inactivated influenza vaccine is well tolerated, stimulates both mucosal and systemic immunity, and potentially protects against influenza illness.
A randomized placebo-controlled double-blind trial of a nasally administered inactivated trivalent influenza vaccine formulated with partially purified meningococcal outer membrane proteins (OMP-TIV) was conducted in 1349 healthy adults aged 18-64 years. Subjects received either vaccine containing 15 μg of haemagglutinin (HA) of each of three influenza strains for the 2003-2004 season on days 0 and 14, or 30 μg on day 0 and saline placebo on day 14, or placebo on days 0 and 14. Vaccination was well tolerated, with similar reactogenicity as placebo. ⋯ In participants receiving all doses of either vaccine regimen the incidence of culture-confirmed influenza with respiratory symptoms and with or without fever was 0.77% (7/904) vs. 2.03% (9/443) in placebo recipients (p=0.045, Fisher's exact test; relative risk reduction 62%), despite circulation of a drift variant A/H3N2 that was poorly matched to vaccine. An OMP-TIV vaccine was well tolerated and reduced risk of symptomatic culture confirmed influenza. Vaccine efficacy will need to be validated in a season with a higher attack rate.
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Estimates of influenza vaccine effectiveness from observational studies that rely on physician-ordered influenza tests may be biased if physician testing behavior is influenced by patient vaccination status. To assess the potential for differential diagnostic testing of children by vaccine status, we examined the association between receipt of a commercial influenza diagnostic test and influenza vaccination among children aged 6-59 months who sought care at the Marshfield Clinic for acute respiratory or febrile illnesses during the 2004-05 through 2007-08 influenza seasons. There was no significant association between prior influenza vaccination and receipt of a diagnostic test for influenza. These findings suggest that estimates of vaccine effectiveness derived from observational studies among children are unlikely to be biased due to differential diagnostic testing.
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Comparative Study
The effectiveness of trivalent inactivated influenza vaccine in children over six consecutive influenza seasons.
To estimate the effectiveness of two doses of trivalent inactivated influenza vaccine (TIV) over six consecutive influenza seasons in a small community in Japan. ⋯ Vaccination with two doses of TIV was consistently effective in preventing influenza-associated clinic visits and hospitalizations.