Effect of influenza vaccine status on winter mortality in Spanish community-dwelling elderly people during 2002-2005 influenza periods.
ABSTRACT This study assessed the relationship between the reception of conventional inactivated influenza vaccine and winter mortality in a prospective cohort that included 11,240 Spanish community-dwelling elderly individuals followed from January 2002 to April 2005. Annual influenza vaccine status was a time-varying condition and primary outcome was all-cause death during study period. Multivariable Cox proportional-hazard models adjusted by age, sex and co-morbidity were used to evaluate vaccine effectiveness. Influenza vaccination was associated with a significant reduction of 23% in winter mortality risk during overall influenza periods. The attributable mortality risk in non-vaccinated people was 24 deaths per 100,000 persons-week within influenza periods, the prevented fraction for the population was 14%, and one death was prevented for every 239 annual vaccinations (ranging from 144 in Winter 2005 to 1748 in Winter 2002).
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ABSTRACT: For the treatment of influenza virus infections, neuraminidase inhibitors (NAIs) that prevent the release of virus particles have been effective against most influenza strains. Several neuraminidase (NA) assays are available for the evaluation of NAIs. To understand the NAI functions under physiological conditions, assays mimicking viral particle release should be useful. We have constructed retrovirus-based reporter viruses that are pseudotyped with hemagglutinin (HA) glycoprotein by transfection of producer cells using plasmids expressing retroviral gag-pol, influenza HA, NA, and firefly luciferase genes. Similarly to the life cycle of influenza viruses, the release of pseudotype viruses also requires neuraminidase functions. This requirement was used to develop an assay to evaluate NAI activities by measuring inhibition of pseudotype virus production at different NAI concentrations. The pseudotype virus release assay was used to determine the IC(50) values of Oseltamivir carboxylate, Zanamivir, and the novel phosphonate congeners of Oseltamivir against N1 group neuraminidases and their H274Y Oseltamivir carboxylate-resistant mutants. The deduced IC(50) values obtained using the release assay correlated with those determined using the fluorogenic substrate 2'-(4-methylumbelliferyl)-alpha-d-N-acetylneuraminic acid (MUNANA) and also correlated with the infectivity results.Antiviral Research 10/2008; 79(3):199-205. DOI:10.1016/j.antiviral.2008.03.002 · 3.94 Impact Factor
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ABSTRACT: This study sought to: describe influenza vaccination coverage among Spanish children, adults, health care workers (HCWs), and immigrants according to the 2006 Spanish National Health Survey (NHS); and analyze the time trend for the period 2003-2006. We analyzed 38,329 questionnaires drawn from the 2006 NHS, covering subjects aged 6 months and over. As the dependent variable, we took the answer to the question, "Did you (or your child) have a 'flu shot in the last campaign?". Independent variables were age group, gender, nationality, occupation (HCWs), and coexistence of chronic conditions. In 2006, vaccination coverage for the Spanish population was: 22.2% overall; 6.8% for all children; and 19.1% for children with a chronic medical condition. Coverages were: 66.8% among subjects aged >/=65 years; 26.6% among high-risk subjects aged <65 years; and 24.2% among HCWs. A significantly lower proportion of immigrants reported vaccination than did indigenous subjects. After controlling for possible confounders, the likelihood of having been vaccinated in 2006 was lower than in 2003 for the entire population (adjusted OR 92, 95%CI 0.86-0.97). In specific target groups, however, coverage underwent a significant reduction from 2003 to 2006 among high-risk subjects aged 16-64 years, and immigrants. Significant improvements were found among subjects aged over 64 years, and children. Available data show unacceptably low levels of influenza vaccination coverage among high-risk subjects aged under 65 years, children with chronic medical conditions, and HCWs. A special effort is thus called for to implement strategies that have demonstrated their effectiveness in enhancing vaccination coverages.The Journal of infection 11/2008; 57(6):472-80. DOI:10.1016/j.jinf.2008.10.005 · 4.02 Impact Factor
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ABSTRACT: Although there is general agreement for the recommendation of the influenza vaccine to elderly and high-risk adults, the magnitude of clinical effectiveness and benefit from the annual vaccination is controversial. In this study, we have assessed the effects of annual influenza vaccination on winter mortality in older adults with chronic heart disease. Cohort study that included 1340 Spanish community-dwelling individuals 65 years or older who had chronic heart disease (congestive heart failure or coronary artery disease) followed from January 2002 to April 2005. Annual influenza vaccine status was a time-varying condition and primary outcome was all-cause death during the study period. Multivariable Cox proportional-hazard models adjusted by age, sex, and comorbidity were used to evaluate vaccine effectiveness. Influenza vaccination was associated with a significant reduction of 37% in the adjusted risk of winter mortality during the overall period 2002-2005. The attributable mortality risk reduction in vaccinated people was 8.2 deaths per 1000 person-winters. We estimated that one death was prevented for every 122 annual vaccinations (ranging between 49 in Winter 2005 and 455 in Winter 2003). Our results suggest a benefit from the influenza vaccination and support an annual vaccination strategy for elderly people with cardiac diseases.European Heart Journal 12/2008; 30(2):209-16. DOI:10.1093/eurheartj/ehn498 · 14.72 Impact Factor