Outbreak of influenza A in an Ontario nursing home--January 1997.

Programme de formation en épidémiologie d'intervention, LLCM, Ottawa.
Canada communicable disease report = Relevé des maladies transmissibles au Canada 08/1997; 23(14):105-8.
Source: PubMed
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    ABSTRACT: Influenza vaccination of elderly individuals is recommended worldwide. Our aim was to review the evidence of efficacy and effectiveness of influenza vaccines in individuals aged 65 years or older. We searched five electronic databases to December, 2004, in any language, for randomised (n=5), cohort (n=49), and case-control (n=10) studies, assessing efficacy against influenza (reduction in laboratory-confirmed cases) or effectiveness against influenza-like illness (reduction in symptomatic cases). We expressed vaccine efficacy or effectiveness as a proportion, using the formula VE=1-relative risk (RR) or VE*=1-odds ratio (OR). We analysed the following outcomes: influenza, influenza-like illness, hospital admissions, complications, and deaths. In homes for elderly individuals (with good vaccine match and high viral circulation) the effectiveness of vaccines against influenza-like illness was 23% (95% CI 6-36) and non-significant against influenza (RR 1.04, 0.43-2.51). Well matched vaccines prevented pneumonia (VE 46%, 30-58) and hospital admission (VE 45%, 16-64) for and deaths from influenza or pneumonia (VE 42%, 17-59), and reduced all-cause mortality (VE 60%, 23-79). In elderly individuals living in the community, vaccines were not significantly effective against influenza (RR 0.19, 0.02-2.01), influenza-like illness (RR 1.05, 0.58-1.89), or pneumonia (RR 0.88, 0.64-1.20). Well matched vaccines prevented hospital admission for influenza and pneumonia (VE 26%, 12-38) and all-cause mortality (VE 42%, 24-55). After adjustment for confounders, vaccine performance was improved for admissions to hospital for influenza or pneumonia (VE* 27%, 21-33), respiratory diseases (VE* 22%, 15-28), and cardiac disease (VE* 24%, 18-30), and for all-cause mortality (VE* 47%, 39-54). In long-term care facilities, where vaccination is most effective against complications, the aims of the vaccination campaign are fulfilled, at least in part. However, according to reliable evidence the usefulness of vaccines in the community is modest.
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    ABSTRACT: Our aim was to review the evidence of efficacy and effectiveness of influenza vaccination of health-care workers in reducing cases of influenza-like illness, influenza, complications from influenza, death from influenza, and death from all causes among the elderly people they care for in institutions. We searched 11 electronic databases in any language and identified two cluster-randomised controlled trials with moderate risk of bias and one cohort study at high risk of bias that addressed our questions. Staff vaccination had a significant effect on influenza-like illness (vaccine effectiveness [VE] 86%, 95% CI 40-97%) only when patients were vaccinated too. If patients were not vaccinated, staff immunisation had no effect. Vaccinating health-care workers did not appear efficacious against influenza (RR 0.87, 95% CI 0.46-1.63). There was no significant effect of vaccination on lower respiratory tract infections: (RR 0.70, 95% CI 0.41-1.20). Deaths from pneumonia were significantly reduced (VE 39%, 95% CI 2-62%), as were deaths from all causes (VE 40%, 95% CI 27-50%). These findings must be interpreted in the light of possible selection, performance, attrition, and detection biases.
    The Lancet Infectious Diseases 06/2006; 6(5):273-9. DOI:10.1016/S1473-3099(06)70462-5 · 19.45 Impact Factor
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    ABSTRACT: Seasonal flu is a very serious public health problem in the elderly due to its morbidity and mortality and financial and social costs arising from this. The aim of this review is to describe the magnitude and importance of seasonal flu in this population group, and its prevention by means of vaccination. For this reason, an updated account of the composition of the vaccine, its dosage and administration route, vaccine safety and the evaluation of the immunogenicity and effectiveness of vaccination. There is variation between different countries and official organisations on the age at which flu vaccination must be established in the elderly. New flu vaccination strategies need to be introduced, to further improve flu vaccination cover in Spain.
    Revista Española de Geriatría y Gerontología 03/2011; 46(2):89-95.