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Browsing by Author "Meijer, Adam"

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  • 2015/16 I-MOVE/I-MOVE+ multicentre case control study in Europe: moderate vaccine effectiveness estimates against influenza A(H1N1)pdm09 and low estimates against lineage mismatched influenza B among children
    Publication . Kissling, Esther; Valenciano, Marta; Pozo, Francisco; Vilcu, Ana-Maria; Reuss, Annicka; Rizzo, Caterina; Larrauri, Amparo; Horváth, Judit Krisztina; Brytting, Mia; Domegan, Lisa; Korczyńska, Monika; Meijer, Adam; Machado, Ausenda; Ivanciuc, Alina; Višekruna Vučina, Vesna; van der Werf, Sylvie; Schweiger, Brunhilde; Bella, Antonino; Gherasim, Alin; Ferenczi, Annamária; Zakikhany, Katherina; O Donnell, Joan; Paradowska-Stankiewicz, Iwona; Dijkstra, Frederika; Guiomar, Raquel; Lazar, Mihaela; Kurečić Filipović, Sanja; Johansen, Kari; Moren, Alain; I-MOVE/I-MOVE+ study team
    Background:During the 2015/16 influenza season in Europe, the co-circulating influenza viruses were A(H1N1)pdm09 and B/Victoria, which was antigenically distinct from the B/Yamagata component in the trivalent influenza vaccine. Methods:We used the test negative design in a multicentre case–control study in twelve European countries to measure 2015/16 influenza vaccine effectiveness (VE) against medically-attended influenza-like illness (ILI) laboratory-confirmed as influenza. General practitioners swabbed a systematic sample of consulting ILI patients ainfluenza Vaccinend a random sample of influenza positive swabs were sequenced. We calculated adjusted VE against influenza A(H1N1)pdm09, A(H1N1)pdm09 genetic group 6B.1 and influenza B overall and by age group. Results: We included 11,430 ILI patients, of which 2272 were influenza A(H1N1)pdm09 and 2901 were influenza B cases. Overall VE against influenza A(H1N1)pdm09 was 32.9% (95% CI: 15.5-46.7). Among those aged 0–14, 15–64 and ≥65  years VE against A(H1N1)pdm09 was 31.9% (95% CI: -32.3-65.0), 41.4% (95%CI: 20.5-56.7) and 13.2% (95% CI: -38.0-45.3) respectively. Overall VE against influenza A(H1N1)pdm09 genetic group 6B.1 was 32.8% (95%CI: -4.1-56.7). Among those aged 0–14, 15–64 and ≥65 years VE against influenza B was -47.6% (95%CI: -124.9-3.1), 27.3% (95%CI: -4.6-49.4), and 9.3% (95%CI: -44.1-42.9) respectively. Conclusions: VE against influenza A(H1N1)pdm09 and its genetic group 6B.1 was moderate in children and adults, and low among individuals ≥65  years. VE against influenza B was low and heterogeneous among age groups. More information on effects of previous vaccination and previous infection are needed to understand the VE results against influenza B in the context of a mismatched vaccine.
    2018-06Journal article Open access Show more
  • COVID-19 vaccine effectiveness against symptomatic infection with SARS-CoV-2 BA.1/BA.2 lineages among adults and adolescents in a multicentre primary care study, Europe, December 2021 to June 2022
    Publication . Lanièce Delaunay, Charlotte; Martínez-Baz, Iván; Sève, Noémie; Domegan, Lisa; Mazagatos, Clara; Buda, Silke; Meijer, Adam; Kislaya, Irina; Pascu, Catalina; Carnahan, AnnaSara; Oroszi, Beatrix; Ilić, Maja; Maurel, Marine; Melo, Aryse; Sandonis Martín, Virginia; Trobajo-Sanmartín, Camino; Enouf, Vincent; McKenna, Adele; Pérez-Gimeno, Gloria; Goerlitz, Luise; de Lange, Marit; Rodrigues, Ana Paula; Lazar, Mihaela; Latorre-Margalef, Neus; Túri, Gergő; Castilla, Jesús; Falchi, Alessandra; Bennett, Charlene; Gallardo, Virtudes; Dürrwald, Ralf; Eggink, Dirk; Guiomar, Raquel; Popescu, Rodica; Riess, Maximilian; Horváth, Judit Krisztina; Casado, Itziar; García, M. del Carmen; Hooiveld, Mariëtte; Machado, Ausenda; Bacci, Sabrina; Kaczmarek, Marlena; Kissling, Esther
    Background: Scarce European data in early 2021 suggested lower vaccine effectiveness (VE) against SARS-CoV-2 Omicron lineages than previous variants. Aim: We aimed to estimate primary series (PS) and first booster VE against symptomatic BA.1/BA.2 infection and investigate potential biases. Methods: This European test-negative multicentre study tested primary care patients with acute respiratory symptoms for SARS-CoV-2 in the BA.1/BA.2-dominant period. We estimated PS and booster VE among adults and adolescents (PS only) for all products combined and for Comirnaty alone, by time since vaccination, age and chronic condition. We investigated potential bias due to correlation between COVID-19 and influenza vaccination and explored effect modification and confounding by prior SARS-CoV-2 infection. Results: Among adults, PS VE was 37% (95% CI: 24–47%) overall and 60% (95% CI: 44–72%), 43% (95% CI: 26–55%) and 29% (95% CI: 13–43%) < 90, 90–179 and ≥ 180 days post vaccination, respectively. Booster VE was 42% (95% CI: 32–51%) overall and 56% (95% CI: 47–64%), 22% (95% CI: 2–38%) and 3% (95% CI: −78% to 48%), respectively. Primary series VE was similar among adolescents. Restricting analyses to Comirnaty had little impact. Vaccine effectiveness was higher among older adults. There was no signal of bias due to correlation between COVID-19 and influenza vaccination. Confounding by previous infection was low, but sample size precluded definite assessment of effect modification. Conclusion: Primary series and booster VE against symptomatic infection with BA.1/BA.2 ranged from 37% to 42%, with similar waning post vaccination. Comprehensive data on previous SARS-CoV-2 infection would help disentangle vaccine- and infection-induced immunity.
    2024-03-28Journal article Open access Show more
  • COVID-19 Vaccine Effectiveness in Autumn and Winter 2022 to 2023 Among Older Europeans
    Publication . Laniece Delaunay, Charlotte; Mazagatos, Clara; Martínez-Baz, Iván; Túri, Gergő; Goerlitz, Luise; Domegan, Lisa; Meijer, Adam; Rodrigues, Ana Paula; Sève, Noémie; Ilić, Maja; Latorre-Margalef, Neus; Lazar, Mihaela; Maurel, Marine; Melo, Aryse; Andreu Ivorra, Blanca; Casado, Itziar; Horváth, Judit Krisztina; Buda, Silke; Bennett, Charlene; de Lange, Marit; Guiomar, Raquel; Enouf, Vincent; Mlinarić, Ivan; Samuelsson Hagey, Tove; Dinu, Sorin; Rumayor, Mercedes; Castilla, Jesús; Oroszi, Beatrix; Dürrwald, Ralf; O’Donnell, Joan; Hooiveld, Mariëtte; Gómez, Verónica; Falchi, Alessandra; Kurečić Filipović, Sanja; Dillner, Lena; Popescu, Rodica; Bacci, Sabrina; Kaczmarek, Marlena; Kissling, Esther; Gallardo García, Virtudes; Perez Morilla, Esteban; Pedrosa Corral, Irene; García Vázquez, Miriam; Milagro-Beamonte, Ana; Fernandez Ibañez, Ana; Margolles Martins, Mario; Giménez Duran, Jaume; Sastre Palou, Bartolomé; López Causapé, Carla; Viloria Raymundo, Luis Javier; Vega Alonso, Tomás; Ordax Díez, Ana; Lozano Alonso, Jose Eugenio; Rojo Bello, Silvia; Mendioroz, Jacobo; Basile, Luca; Martínez Mateo, Ana Isabel; Ruiz de Porras, Carlota; Moya Garcés, Alba; Marcos, Mª Ángeles; López Maside, Aurora; Botella Quijal, Francesc; Miralles Espi, Maite; Andreu Salete, Cristina; García Rodríguez, María del Carmen; Linares, Juan Antonio; García Comas, Luis; Barranco, Mª Isabel; Chirlaque, María-Dolores; Moreno Docón, Antonio; Ramos Marín, Violeta; Castrillejo, Daniel; Gómez Anés, Atanasio; Larrauro, Amparo; Pérez-Gimeno, Gloria; Lozano Álvarez, Marcos; Vega, Lorena; Galindo, Silvia; Puma, Tania; Monge, Susana; Pozo, Francisco; Casas, Inmaculada; Sandonis, Virginia; Vázquez-Morón, Sonia; Echeverría, Aitziber; Trobajo-Sanmartín, Camino; García Cenoz, Manuel; Ezpeleta, Guillermo; Ezpeleta, Carmen; Navascués, Ana; Krisztalovics, Katalin; Mucsányiné Juhász, Krisztina; Kristóf, Katalin; Preuss, Ute; Wedde, Marianne; Biere, Barbara; Reiche, Janine; Oh, Djin-Ye; McKenna, Adele; Connell, Jeff; Joyce, Michael; Bagheri, Mariam; Bos, Sanne; van den Brink, Sharon; Dijkstra, Frederika; Eggink, Dirk; van Gageldonk-Lafeber, Rianne; Goderski, Gabriel; Herrebrugh, Chantal; Jenniskens, Liz; Reukers, Daphne; Sluimer, John; Sprong, Tara; Teirlinck, Anne; Veldhijzen, Nienke; van der Burgh, Ruben; Kager, Cathrien; Klinkhamer, Mayra; Knottnerus, Bart; Riethof, Marloes; van den Broek, Ruud; Wortel, Safira; Machado, Ausenda; Kislaya, Irina; Aniceto, Carlos; Gomes, Licínia; Verdasca, Nuno; Henriques, Camila; Dias, Daniela; Lança, Miguel; Blanchon, Thierry; Guerrisi, Caroline; Renard, Aubane; Launay, Titouan; Masse, Shirley; Chazelle, Marie; Ferenčak, Ivana; Kaić, Bernard; Višekruna Vučina, Vesna; Čusek Adamić, Katica; Kosanović Ličina, Mirjana Lana; Lakošeljac, Danijela; Mihin Huskić, Ivana; Nonković, Diana; Carnahan, Annasara; Hansson-Pihlainen, Eva; Arvesen, Elin; Nid, Nora; Hansen, Anna-Lena; Andersson, Emmi; Dillner, Lena; Jidovu, Adrian; Timnea, Olivia Carmen; Pascu, Cătălina; Oprea, Mihaela; Bistriceanu, Iulia; Ivanciuc, Alina; Mihai, Maria Elena; VEBIS Primary Care Vaccine Effectiveness Group
    Key Points: - Question: What was the effectiveness of COVID-19 vaccines administered in autumn and winter 2022 to 2023 against symptomatic SARS-CoV-2 infection among people aged 60 years or older in Europe, and how did different exposed or reference groups affect effectiveness? - Findings: In this case-control study of 9308 primary care patients at 11 European sites, within 3 months of vaccination, all COVID-19 vaccine effectiveness (CVE) estimates were 29% to 39% against SARS-CoV-2 viruses and 44% to 52% against the XBB variants. All point estimates decreased by time after vaccination, with no vaccine protection after 6 months. - Meaning: Findings of this study suggest that COVID-19 vaccination campaigns should precede peaks in SARS-CoV-2 incidence and that effectiveness of new vaccines against emerging variants should be continually monitored using seasonal CVE approaches.
    2024-07-01Journal article Open access Show more
  • Determinants of fatal outcome in patients admitted to intensive care units with influenza, European Union 2009–2017
    Publication . Penttinen, Pasi; Snacken, René; Lyytikäinen, Outi; Ikonen, Niina; Melillo, Tanya; Melillo, Jackie M.; Staroňová, Edita; Mikas, Ján; Popow-Kraupp, Theresia; Orta Gomes, Carlos M.; Guiomar, Raquel; Slezák, Pavel; Kynčl, Jan; Meijer, Adam; Van Gageldonk-Lafeber, Arianne B.; Domegan, Lisa; O’Donnell, Joan; Lupulescu, Emilia; Popovici, Odette; Carnahan, Annasara; Brytting, Mia; Delgado-Sanz, Concepción; Oliva Domínguez, Jesús A.; Larrauri, Amparo; Hubert, Bruno; Bonmarin, Isabelle; Gomes Dias, Joana; Adlhoch, Cornelia
    Background: Morbidity, severity, and mortality associated with annual influenza epidemics are of public health concern. We analyzed surveillance data on hospitalized laboratory-confirmed influenza cases admitted to intensive care units to identify common determinants for fatal outcome and inform and target public health prevention strategies, including risk communication. Methods: We performed a descriptive analysis and used Poisson regression models with robust variance to estimate the association of age, sex, virus (sub)type, and underlying medical condition with fatal outcome using European Union data from 2009 to 2017. Results: Of 13 368 cases included in the basic dataset, 2806 (21%) were fatal. Age ≥40 years and infection with influenza A virus were associated with fatal outcome. Of 5886 cases with known underlying medical conditions and virus A subtype included in a more detailed analysis, 1349 (23%) were fatal. Influenza virus A(H1N1)pdm09 or A(H3N2) infection, age ≥60 years, cancer, human immunodeficiency virus infection and/or other immune deficiency, and heart, kidney, and liver disease were associated with fatal outcome; the risk of death was lower for patients with chronic lung disease and for pregnant women. Conclusions: This study re-emphasises the importance of preventing influenza in the elderly and tailoring strategies to risk groups with underlying medical conditions.
    2019-10-29Journal article Open access Show more
  • Effectiveness of complete primary vaccination against COVID-19 at primary care and community level during predominant Delta circulation in Europe: multicentre analysis, I-MOVE-COVID-19 and ECDC networks, July to August 2021
    Publication . Kissling, Esther; Hooiveld, Mariëtte; Martínez-Baz, Iván; Mazagatos, Clara; William, Naoma; Vilcu, Ana-Maria; Kooijman, Marjolein N.; Ilić, Maja; Domegan, Lisa; Machado, Ausenda; de Lusignan, Simon; Lazar, Mihaela; Meijer, Adam; Brytting, Mia; Casado, Itziar; Larrauri, Amparo; Murray, Josephine-L.K.; Behillil, Sylvie; de Gier, Brechje; Mlinarić, Ivan; O’Donnell, Joan; Rodrigues, Ana Paula; Tsang, Ruby; Timnea, Olivia; de Lange, Marit; Riess, Maximilian; Castilla, Jesús; Pozo, Francisco; Hamilton, Mark; Falchi, Alessandra; Knol, Mirjam J.; Kurečić Filipović, Sanja; Dunford, Linda; Guiomar, Raquel; Cogdale, Jade; Cherciu, Carmen; Jansen, Tessa; Enkirch, Theresa; Basile, Luca; Connell, Jeff; Gómez, Verónica; Sandonis Martín, Virginia; Bacci, Sabrina; Rose, Angela M.C.; Pastore Celentano, Lucia; Valenciano, Marta; I-MOVE-COVID-19 and ECDC primary care study teams
    Introduction: In July and August 2021, the SARS-CoV-2 Delta variant dominated in Europe. Aim: Using a multicentre test-negative study, we measured COVID-19 vaccine effectiveness (VE) against symptomatic infection. Methods: Individuals with COVID-19 or acute respiratory symptoms at primary care/community level in 10 European countries were tested for SARS-CoV-2. We measured complete primary course overall VE by vaccine brand and by time since vaccination. Results: Overall VE was 74% (95% CI: 69–79), 76% (95% CI: 71–80), 63% (95% CI: 48–75) and 63% (95% CI: 16–83) among those aged 30–44, 45–59, 60–74 and ≥ 75 years, respectively. VE among those aged 30–59 years was 78% (95% CI: 75–81), 66% (95% CI: 58–73), 91% (95% CI: 87–94) and 52% (95% CI: 40–61), for Comirnaty, Vaxzevria, Spikevax and COVID-19 Vaccine Janssen, respectively. VE among people 60 years and older was 67% (95% CI: 52–77), 65% (95% CI: 48–76) and 83% (95% CI: 64–92) for Comirnaty, Vaxzevria and Spikevax, respectively. Comirnaty VE among those aged 30–59 years was 87% (95% CI: 83–89) at 14–29 days and 65% (95% CI: 56–71%) at ≥ 90 days between vaccination and onset of symptoms. Conclusions: VE against symptomatic infection with the SARS-CoV-2 Delta variant varied among brands, ranging from 52% to 91%. While some waning of the vaccine effect may be present (sample size limited this analysis to only Comirnaty), protection was 65% at 90 days or more between vaccination and onset.
    2022-05-26Journal article Open access Show more
  • Effectiveness of COVID-19 vaccines administered in the 2023 autumnal campaigns in Europe: Results from the VEBIS primary care test-negative design study, September 2023–January 2024
    Publication . Laniece Delaunay, Charlotte; Melo, Aryse; Maurel, Marine; Mazagatos, Clara; Goerlitz, Luise; O’Donnell, Joan; Oroszi, Beatrix; Sève, Noémie; Rodrigues, Ana Paula; Martínez-Baz, Iván; Meijer, Adam; Mlinarić, Ivan; Latorre-Margalef, Neus; Lazăr, Mihaela; Pérez-Gimeno, Gloria; Dürrwald, Ralf; Bennett, Charlene; Túri, Gergő; Rameix-Welti, Marie-Anne; Guiomar, Raquel; Castilla, Jesús; Hooiveld, Mariëtte; Kurečić Filipović, Sanja; Samuelsson Hagey, Tove; Dijkstra, Frederika; Borges, Vitor; Ramos Marín, Violeta; Bacci, Sabrina; Kaczmarek, Marlena; Kissling, Esther; European primary care VE group
    In autumn 2023, European vaccination campaigns predominantly administered XBB.1.5 vaccine. In a European multicentre study, we estimated 2023 COVID-19 vaccine effectiveness (VE) against laboratory-confirmed symptomatic infection at primary care level between September 2023 and January 2024. Using a testnegative case–control design, we estimated VE in the target group for COVID-19 vaccination overall and by time since vaccination. We included 1057 cases and 4397 controls. Vaccine effectiveness was 40 % (95 % CI: 26–53 %) overall, 48 % (95 % CI: 31–61 %) among those vaccinated < 6 weeks of onset and 29 % (95 % CI: 3–49 %) at 6–14 weeks. Our results suggest that COVID-19 vaccines administered to target groups during the autumn 2023 campaigns showed clinically significant effectiveness against laboratory-confirmed, medically attended symptomatic SARS-CoV-2 infection in the 3 months following vaccination. A longer study period will allow for further variant-specific COVID-19 VE estimates, better understanding decline in VE and informing booster administration policies.
    2024-06-04Journal article Open access Show more
  • Effectiveness of influenza vaccine against influenza A in Europe in seasons of different A(H1N1)pdm09 and the same A(H3N2) vaccine components (2016-17 and 2017-18)
    Publication . Kissling, Esther; Pozo, Francisco; Buda, Silke; Vilcu, Ana-Maria; Rizzo, Caterina; Gherasim, Alin; Krisztina Horváth, Judit; Brytting, Mia; Domegan, Lisa; Meijer, Adam; Paradowska-Stankiewicz, Iwona; Machado, Ausenda; Višekruna Vučina, Vesna; Lazar, Mihaela; Johansen, Kari; Dürrwald, Ralf; van der Werf, Sylvie; Bella, Antonino; Larrauri, Amparo; Ferenczi, Annamária; Zakikhany, Katherina; O'Donnell, Joan; Dijkstra, Frederika; Bogusz, Joanna; Guiomar, Raquel; Kurečić Filipović, Sanja; Pitigoi, Daniela; Penttinen, Pasi; Valenciano, Marta; Gomez, Veronica; Kislaya, Irina; Nunes, Baltazar; I-MOVE/I-MOVE+ study team
    Introduction: Influenza A(H3N2) viruses predominated in Europe in 2016–17. In 2017–18 A(H3N2) and A(H1N1)pdm09 viruses co-circulated. The A(H3N2) vaccine component was the same in both seasons; while the A(H1N1)pdm09 component changed in 2017–18. In both seasons, vaccine seed A(H3N2) viruses developed adaptations/alterations during propagation in eggs, impacting antigenicity. Methods: We used the test-negative design in a multicentre primary care case-control study in 12 European countries to measure 2016–17 and 2017–18 influenza vaccine effectiveness (VE) against laboratory-confirmed influenza A(H1N1)pdm09 and A(H3N2) overall and by age group. Results: During the 2017–18 season, the overall VE against influenza A(H1N1)pdm09 was 59% (95% CI: 47–69). Among those aged 0–14, 15–64 and ≥65 years, VE against A(H1N1)pdm09 was 64% (95% CI: 37–79), 50% (95% CI: 28–66) and 66% (95% CI: 42–80), respectively. Overall VE against influenza A(H3N2) was 28% (95% CI: 17–38) in 2016–17 and 13% (95% CI: -15 to 34) in 2017–18. Among 0–14-year-olds VE against A(H3N2) was 28% (95%CI: -10 to 53) and 29% (95% CI: -87 to 73), among 15–64-year-olds 34% (95% CI: 18–46) and 33% (95% CI: -3 to 56) and among those aged ≥65 years 15% (95% CI: -10 to 34) and -9% (95% CI: -74 to 32) in 2016–17 and 2017–18, respectively. Conclusions: Our study suggests the new A(H1N1)pdm09 vaccine component conferred good protection against circulating strains, while VE against A(H3N2) was <35% in 2016–17 and 2017–18. The egg propagation derived antigenic mismatch of the vaccine seed virus with circulating strains may have contributed to this low effectiveness. A(H3N2) seed viruses for vaccines in subsequent seasons may be subject to the same adaptations; in years with lower than expected VE, recommendations of preventive measures other than vaccination should be given in a timely manner.
    2019-09-17Journal article Open access Show more
  • Effectiveness of XBB.1.5 Vaccines Against Symptomatic SARS‐CoV‐2 Infection in Older Adults During the JN.1 Lineage‐Predominant Period, European VEBIS Primary Care Multicentre Study, 20 November 2023–1 March 2024
    Publication . Merdrignac, Lore; Laniece Delaunay, Charlotte; Verdasca, Nuno; Vega‐Piris, Lorena; O'Donnell, Joan; Sève, Noémie; Trobajo‐Sanmartín, Camino; Buda, Silke; Hooiveld, Mariëtte; Rodrigues, Ana Paula; Túri, Gergő; Latorre‐Margalef, Neus; Mlinarić, Ivan; Lazar, Mihaela; Maurel, Marine; Castrillejo, Daniel; Bennett, Charlene; Rameix‐Welti, Marie‐Anne; Martínez‐Baz, Iván; Dürrwald, Ralf; Meijer, Adam; Melo, Aryse; Oroszi, Beatrix; Hagey, Tove Samuelsson; Kurečić Filipović, Sanja; Dijkstra, Frederika; Gómez, Verónica; Bacci, Sabrina; Kaczmarek, Marlena; Kissling, Esther; VEBIS Primary Care Vaccine Effectiveness Group
    We estimated XBB.1.5 vaccine effectiveness (VE) against symptomatic SARS-CoV-2 infection among adults aged ≥65 years during the 2023/2024 JN.1 lineage-predominant period in a European multi-country test-negative case–control study at primary care level. We estimated VE adjusted by study site, age, sex, chronic conditions and onset date. We included 220 cases and 1733 controls. The VE was 48% (95% CI: 12–71), 23% (95% CI: −11–48) and 5% (95% CI: −92–56) among those with symptom onset 1–5, 6–11, and ≥12weeks after vaccination, respectively. XBB.1.5 vaccine provided short and moderate protection against JN.1 symptomatic infection.
    2024-11-10Journal article Open access Show more
  • Exploring the effect of clinical case definitions on influenza vaccine effectiveness estimation at primary care level: Results from the end-of-season 2022–23 VEBIS multicentre study in Europe
    Publication . Maurel, Marine; Mazagatos, Clara; Goerlitz, Luise; Oroszi, Beatrix; Hooiveld, Mariette; Machado, Ausenda; Domegan, Lisa; Ilić, Maja; Popescu, Rodica; Sève, Noémie; Martínez-Baz, Iván; Larrauri, Amparo; Buda, Silke; Túri, Gergő; Meijer, Adam; Gómez, Verónica; O'Donnell, Joan; Mlinarić, Ivan; Timnea, Olivia; Diez, Ana Ordax; Dürrwald, Ralf; Horváth, Judit Krisztina; Dijkstra, Frederika; Rodrigues, Ana Paula; McKenna, Adele; Filipović, Sanja Kurečić; Lazar, Mihaela; Kaczmarek, Marlena; Bacci, Sabrina; Kissling, Esther; VEBIS study team
    Background: Within influenza vaccine effectiveness (VE) studies at primary care level with a laboratory-confirmed outcome, clinical case definitions for recruitment of patients can vary. We used the 2022-23 VEBIS primary care European multicentre study end-of-season data to evaluate whether the clinical case definition affected IVE estimates. Methods: We estimated VE using a multicentre test-negative case-control design. We measured VE against any influenza and influenza (sub)types, by age group (0-14, 15-64, ≥65 years) and by influenza vaccine target group, using logistic regression. We estimated IVE among patients meeting the European Union (EU) acute respiratory infection (ARI) case definition and among those meeting the EU influenza-like illness (ILI) case definition, including only sites providing information on specific symptoms and recruiting patients using an ARI case definition (as the EU ILI case definition is a subset of the EU ARI one). Results: We included 24 319 patients meeting the EU ARI case definition, of whom 21 804 patients (90 %) meet the EU ILI case definition, for the overall pooled VE analysis against any influenza. The overall and influenza (sub)type-specific VE varied by ≤2 % between EU ILI and EU ARI populations. Discussion: Among all analyses, we found similar VE estimates between the EU ILI and EU ARI populations, with few (10%) additional non-ILI ARI patients recruited. These results indicate that VE in the 2022-23 influenza season was not affected by use of a different clinical case definition for recruitment, although we recommend investigating whether this holds true for next seasons.
    2024-05-03Journal article Open access Show more
  • Exploring the effect of previous inactivated influenza vaccination on seasonal influenza vaccine effectiveness against medically attended influenza: results of the European I-MOVE multicentre test-negative case-control study, 2011/2012-2016/2017
    Publication . Valenciano, Marta; Kissling, Esther; Larrauri, Amparo; Nunes, Baltazar; Pitigoi, Daniela; O'Donnell, Joan; Reuss, Annicka; Horváth, Judit Krisztina; Paradowska-Stankiewicz, Iwona; Rizzo, Caterina; Falchi, Alessandra; Daviaud, Isabelle; Brytting, Mia; Meijer, Adam; Kaic, Bernard; Gherasim, Alin; Machado, Ausenda; Ivanciuc, Alina; Domegan, Lisa; Schweiger, Brunhilde; Ferenczi, Annamária; Korczyńska, Monika; Bella, Antonino; Vilcu, Ana-Maria; Mosnier, Anne; Zakikhany, Katherina; de Lange, Marit; Kurečić Filipovićović, Sanja; Johansen, Kari; Moren, Alain; I-MOVE primary care multicentre case-control team
    BACKGROUND: Results of previous influenza vaccination effects on current season influenza vaccine effectiveness (VE) are inconsistent. OBJECTIVES: To explore previous influenza vaccination effects on current season VE among population targeted for vaccination. METHODS: We used 2011/2012 to 2016/2017 I-MOVE primary care multicentre test-negative data. For each season, we compared current season adjusted VE (aVE) between individuals vaccinated and unvaccinated in previous season. Using unvaccinated in both seasons as a reference, we then compared aVE between vaccinated in both seasons, current only, and previous only. RESULTS: We included 941, 2645 and 959 influenza-like illness patients positive for influenza A(H1N1)pdm09, A(H3N2) and B, respectively, and 5532 controls. In 2011/2012, 2014/2015 and 2016/2017, A(H3N2) aVE point estimates among those vaccinated in previous season were -68%, -21% and -19%, respectively; among unvaccinated in previous season, these were 33%, 48% and 46%, respectively (aVE not computable for influenza A(H1N1)pdm09 and B). Compared to current season vaccination only, VE for both seasons' vaccination was (i) similar in two of four seasons for A(H3N2) (absolute difference [ad] 6% and 8%); (ii) lower in three of four seasons for influenza A(H1N1)pdm09 (ad 18%, 26% and 29%), in two seasons for influenza A(H3N2) (ad 27% and 39%) and in two of three seasons for influenza B (ad 26% and 37%); (iii) higher in one season for influenza A(H1N1)pdm09 (ad 20%) and influenza B (ad 24%). CONCLUSIONS: We did not identify any pattern of previous influenza vaccination effect. Prospective cohort studies documenting influenza infections, vaccinations and vaccine types are needed to understand previous influenza vaccinations' effects.
    2018-09Journal article Open access Show more