I-Move towards monitoring seasonal and pandemic influenza vaccine effectiveness...

• Author(s): Kissling, E. ; Valenciano, M. ; Falcao, J. ; Larrauri, A. ; Widgren, K. ; Pitigoi, D. ; Oroszi, B. ; Nunes, B. ; Savulescu, C. ; Mazick, A. ; Lupulescu, E. ; Ciancio, B. ; Moren, A.
• Date: 2009
• Persistent ID: http://hdl.handle.net/10400.18/700
• Origin: Repositório Científico do Instituto Nacional de Saúde
• Subject(s): Estados de Saúde e de Doença; Epidemiologia; Influenza; Seasonal Vaccine; Pandemic Influenza Vaccine; Effectiveness
• Document Type: Article
• Language: English

Description

Within I-MOVE (European programme to monitor seasonal and pandemic influenza vaccine effectiveness (IVE)) five countries conducted IVE pilot case-control studies in 2008-9. One hundred and sixty sentinel general practitioners (GP) swabbed all elderly consulting for influenza-like illness (ILI). Influenza confirmed cases were compared to influenza negative controls. We conducted a pooled analysis to obtain a summary IVE in the age group of >or=65 years. We measured IVE in each study and assessed heterogeneity between studies qualitatively and using the I2 index. We used a one-stage pooled model with study as a fixed effect. We adjusted estimates for age-group, sex, chronic diseases, smoking, functional status, previous influenza vaccinations and previous hospitalisations. The pooled analysis included 138 cases and 189 test-negative controls. There was no statistical heterogeneity (I2=0) between studies but ILI case definition, previous hospitalisations and functional status were slightly different. The adjusted IVE was 59.1% (95% CI: 15.3-80.3%). IVE was 65.4% (95% CI: 15.6-85.8%) in the 65-74, 59.6% (95% CI: -72.6 -90.6%) in the age group of >or=75 and 56.4% (95% CI: -0.2-81.3%) for A(H3). Pooled analysis is feasible among European studies. The variables definitions need further standardisation. Larger sample sizes are needed to achieve greater precision for subgroup analysis. For 2009-10, I-MOVE will extend the study to obtain early IVE estimates in groups targeted for pandemic H1N1 influenza vaccination.