b2e3e23cab329bd7c23cdcfdaef7db18 320343.pdf ff7831c29e4d3d33686c9c6b9b9df5ae2927c998 320343.pdf 48a8c03cda2211743ceafea6902c2cf483c08e221f10d84bd05420fea8b4a8d6 320343.pdf Title: Influenza Vaccine Effectiveness against Hospitalization, Season 2021/22: A Test-Negative Design Study in Barcelona Subject: Background: Vaccination is considered the most effective measure for preventing influenza and its complications. The influenza vaccine effectiveness (IVE) varies annually due to the evolution of influenza viruses and the update of vaccine composition. Assessing the IVE is crucial to facilitate decision making in public health policies. Aim: to estimate the IVE against hospitalization and its determinants in the 2021/22 season in a Spanish tertiary hospital. Methods: We conducted a prospective observational test-negative design study within the Development of Robust and Innovative Vaccine Effectiveness (DRIVE) project. Hospitalized patients with severe acute respiratory infection (SARI) and an available influenza reverse transcription polymerase chain reaction (RT-PCR) were selected and classified as cases (positive influenza RT-PCR) or controls (negative influenza RT-PCR). Vaccine information was obtained from electronic clinical records shared by public healthcare providers. Information about potential confounders was obtained from hospital clinical registries. The IVE was calculated by subtracting the ratio of the odds of vaccination in cases and controls from one, as a percentage (IVE = (1 - odds ratio (OR)) 100). Multivariate IVE estimates were calculated using logistic regression. Results: In total, 260 severe acute respiratory infections (SARI) were identified, of which 34 were positive for influenza, and all were subtype A(H3N2). Fifty-three percent were vaccinated. Adjusted IVE against hospitalization was 26.4% (95% CI -69% to 112%). IVE determinants could not be explored due to sample size limitations. Conclusion: Our data revealed non-significant moderate vaccine effectiveness against hospitalization for the 2021/2022 season. Keywords: influenza; vaccine; effectiveness; hospitalization Author: Mar Fornaguera, Oleguer Parés-Badell, Íngrid Carbonés-Fargas, Cristina Andrés, José Ángel Rodrigo-Pendás, Blanca Borras-Bermejo, Lluís Armadans-Gil, Gabriela Tejada, David Guananga, Martí Vivet-Escalé, Arnau Peñalver-Piñol, Irene Torrecilla-Martínez, Arnau del Oso, Xavier Martínez-Gómez, Andres Antón and Susana Otero-Romero Creator: LaTeX with hyperref Producer: pdfTeX-1.40.21 CreationDate: Wed Sep 20 05:50:00 2023 CEST ModDate: Wed Sep 20 05:52:09 2023 CEST Custom Metadata: no Metadata Stream: no Tagged: no UserProperties: no Suspects: no Form: none JavaScript: no Pages: 11 Encrypted: no Page size: 595.276 x 841.89 pts (A4) Page rot: 0 File size: 982429 bytes Optimized: no PDF version: 1.7 name type encoding emb sub uni object ID ------------------------------------ ----------------- ---------------- --- --- --- --------- RMXANV+VnURWPalladioL Type 1 Custom yes yes no 10 0 HNHPNJ+URWPalladioL-Bold Type 1 Custom yes yes no 15 0 BNFHAP+URWPalladioL-Roma Type 1 Custom yes yes no 20 0 TMBAQG+URWPalladioL-Ital Type 1 Custom yes yes no 24 0 AINHDX+CMSY10 Type 1 Builtin yes yes no 28 0 PBPAFQ+VnURWPalladioL-Bold Type 1 Custom yes yes no 32 0 MKBLML+PalatinoLinotype,Bold TrueType WinAnsi yes yes no 79 0 MKBLMM+PalatinoLinotype CID TrueType Identity-H yes yes yes 82 0 MKBLMN+PalatinoLinotype TrueType WinAnsi yes yes no 88 0 MKBLMP+PalatinoLinotype,Italic TrueType WinAnsi yes yes no 91 0 MKBMHN+PalatinoLinotype TrueType MacRoman yes yes no 94 0 BCDEEE+PalatinoLinotype-Bold TrueType WinAnsi yes yes no 109 0 BCDFEE+PalatinoLinotype-Roman TrueType WinAnsi yes yes no 113 0 BCDGEE+PalatinoLinotype-Italic TrueType WinAnsi yes yes no 117 0 BCDIEE+PalatinoLinotype-Bold CID TrueType Identity-H yes yes yes 121 0 BCDJEE+PalatinoLinotype-Roman CID TrueType Identity-H yes yes yes 128 0 BCDKEE+PalatinoLinotype-BoldItalic TrueType WinAnsi yes yes no 135 0 QLBIEB+URWPalladioL-BoldItal Type 1 Custom yes yes no 144 0 Jhove (Rel. 1.28.0, 2023-05-18) Date: 2025-10-29 04:43:31 CET RepresentationInformation: 320343.pdf ReportingModule: PDF-hul, Rel. 1.12.4 (2023-03-16) LastModified: 2025-10-28 10:27:12 CET Size: 982429 Format: PDF Version: 1.7 Status: Well-Formed and valid SignatureMatches: PDF-hul MIMEtype: application/pdf PDFMetadata: Objects: 299 FreeObjects: 1 IncrementalUpdates: 0 DocumentCatalog: PageLayout: SinglePage PageMode: UseNone Outlines: Item: Title: Introduction Destination: section.1 Item: Title: Methods Destination: section.2 Children: Item: Title: Study Design and Population Destination: subsection.2.1 Item: Title: Sample Size Destination: subsection.2.2 Item: Title: Data and Sources of Information Destination: subsection.2.3 Item: Title: Ethical Statement Destination: section.3 Item: Title: Statistical Analysis Destination: section.4 Item: Title: Results Destination: section.5 Item: Title: Discussion Destination: section.6 Item: Title: Conclusions Destination: section.7 Item: Title: References Destination: section.8 Info: Title: Influenza Vaccine Effectiveness against Hospitalization, Season 2021/22: A Test-Negative Design Study in Barcelona Author: Mar Fornaguera, Oleguer Parés-Badell, Íngrid Carbonés-Fargas, Cristina Andrés, José Ángel Rodrigo-Pendás, Blanca Borras-Bermejo, Lluís Armadans-Gil, Gabriela Tejada, David Guananga, Martí Vivet-Escalé, Arnau Peñalver-Piñol, Irene Torrecilla-Martínez, Arnau del Oso, Xavier Martínez-Gómez, Andres Antón and Susana Otero-Romero Subject: Background: Vaccination is considered the most effective measure for preventing influenza and its complications. The influenza vaccine effectiveness (IVE) varies annually due to the evolution of influenza viruses and the update of vaccine composition. Assessing the IVE is crucial to facilitate decision making in public health policies. Aim: to estimate the IVE against hospitalization and its determinants in the 2021/22 season in a Spanish tertiary hospital. Methods: We conducted a prospective observational test-negative design study within the Development of Robust and Innovative Vaccine Effectiveness (DRIVE) project. Hospitalized patients with severe acute respiratory infection (SARI) and an available influenza reverse transcription polymerase chain reaction (RT-PCR) were selected and classified as cases (positive influenza RT-PCR) or controls (negative influenza RT-PCR). Vaccine information was obtained from electronic clinical records shared by public healthcare providers. Information about potential confounders was obtained from hospital clinical registries. The IVE was calculated by subtracting the ratio of the odds of vaccination in cases and controls from one, as a percentage (IVE = (1 - odds ratio (OR)) 100). Multivariate IVE estimates were calculated using logistic regression. Results: In total, 260 severe acute respiratory infections (SARI) were identified, of which 34 were positive for influenza, and all were subtype A(H3N2). Fifty-three percent were vaccinated. Adjusted IVE against hospitalization was 26.4% (95% CI -69% to 112%). IVE determinants could not be explored due to sample size limitations. Conclusion: Our data revealed non-significant moderate vaccine effectiveness against hospitalization for the 2021/2022 season. 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