Influenza Vaccine Effectiveness in Preventing Laboratory-Confirmed Influenza Cases and Hospitalizations in Navarre, Spain, 2022–2023
We estimated influenza vaccine effectiveness (IVE) in preventing outpatient and hospitalized cases in the 2022–2023 season. A test-negative design included a representative sample of outpatients and all hospitalized patients with influenza-like illness (ILI) from October 2022 to May 2023 in Navarre,...
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| Format: | Article |
| Language: | English |
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MDPI AG
2023-09-01
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| Series: | Vaccines |
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| Online Access: | https://www.mdpi.com/2076-393X/11/9/1478 |
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| author | Iván Martínez-Baz Miguel Fernández-Huerta Ana Navascués Francisco Pozo Camino Trobajo-Sanmartín Itziar Casado Aitziber Echeverria Carmen Ezpeleta Jesús Castilla |
| author_facet | Iván Martínez-Baz Miguel Fernández-Huerta Ana Navascués Francisco Pozo Camino Trobajo-Sanmartín Itziar Casado Aitziber Echeverria Carmen Ezpeleta Jesús Castilla |
| author_sort | Iván Martínez-Baz |
| collection | DOAJ |
| description | We estimated influenza vaccine effectiveness (IVE) in preventing outpatient and hospitalized cases in the 2022–2023 season. A test-negative design included a representative sample of outpatients and all hospitalized patients with influenza-like illness (ILI) from October 2022 to May 2023 in Navarre, Spain. ILI patients were tested by PCR for influenza virus. Influenza vaccination status was compared between confirmed influenza cases and test-negative controls. Among 3321 ILI patients tested, IVE to prevent influenza cases was 34% (95% confidence interval (CI): 16 to 48) overall, 85% (95%CI: 63 to 94) against influenza B, and 28% (95%CI: 3 to 46) against A(H3N2). Among 558 outpatients, 222 (40%) were confirmed for influenza: 55% A(H3N2), 11% A(H1N1), and 31% B. Overall, IVE to prevent outpatient cases was 48% (95%CI: 8 to 70), 88% (95%CI: 3 to 98) against influenza B, and 50% (95%CI: −4 to 76) against A(H3N2). Of 2763 hospitalized patients, 349 (13%) were positive for influenza: 64% A(H3N2), 17% A(H1N1), and 8% B. IVE to prevent hospitalization was 24% (95%CI: −1 to 42) overall, 82% (95%CI: 49 to 93) against influenza B, and 16% (95%CI: −17 to 40) against A(H3N2). No IVE was observed in preventing influenza A(H1N1). IVE was high to prevent influenza B, moderate against A(H3N2) and null against A(H1N1). A lower proportion of influenza B cases may explain the smaller IVE in hospitalized patients than in outpatients. The null IVE against A(H1N1) was consistent with the observed antigenic drift and supports the new composition of the 2023–2024 influenza vaccine. |
| first_indexed | 2024-03-10T21:52:20Z |
| format | Article |
| id | doaj.art-2d575ac91cae4d69b9c7e30e391eca36 |
| institution | Directory Open Access Journal |
| issn | 2076-393X |
| language | English |
| last_indexed | 2024-03-10T21:52:20Z |
| publishDate | 2023-09-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Vaccines |
| spelling | doaj.art-2d575ac91cae4d69b9c7e30e391eca362023-11-19T13:19:31ZengMDPI AGVaccines2076-393X2023-09-01119147810.3390/vaccines11091478Influenza Vaccine Effectiveness in Preventing Laboratory-Confirmed Influenza Cases and Hospitalizations in Navarre, Spain, 2022–2023Iván Martínez-Baz0Miguel Fernández-Huerta1Ana Navascués2Francisco Pozo3Camino Trobajo-Sanmartín4Itziar Casado5Aitziber Echeverria6Carmen Ezpeleta7Jesús Castilla8Instituto de Salud Pública de Navarra, 31003 Pamplona, SpainNavarre Institute for Health Research (IdiSNA), 31008 Pamplona, SpainNavarre Institute for Health Research (IdiSNA), 31008 Pamplona, SpainCIBER Epidemiología y Salud Pública (CIBERESP), 28029 Madrid, SpainInstituto de Salud Pública de Navarra, 31003 Pamplona, SpainInstituto de Salud Pública de Navarra, 31003 Pamplona, SpainInstituto de Salud Pública de Navarra, 31003 Pamplona, SpainNavarre Institute for Health Research (IdiSNA), 31008 Pamplona, SpainInstituto de Salud Pública de Navarra, 31003 Pamplona, SpainWe estimated influenza vaccine effectiveness (IVE) in preventing outpatient and hospitalized cases in the 2022–2023 season. A test-negative design included a representative sample of outpatients and all hospitalized patients with influenza-like illness (ILI) from October 2022 to May 2023 in Navarre, Spain. ILI patients were tested by PCR for influenza virus. Influenza vaccination status was compared between confirmed influenza cases and test-negative controls. Among 3321 ILI patients tested, IVE to prevent influenza cases was 34% (95% confidence interval (CI): 16 to 48) overall, 85% (95%CI: 63 to 94) against influenza B, and 28% (95%CI: 3 to 46) against A(H3N2). Among 558 outpatients, 222 (40%) were confirmed for influenza: 55% A(H3N2), 11% A(H1N1), and 31% B. Overall, IVE to prevent outpatient cases was 48% (95%CI: 8 to 70), 88% (95%CI: 3 to 98) against influenza B, and 50% (95%CI: −4 to 76) against A(H3N2). Of 2763 hospitalized patients, 349 (13%) were positive for influenza: 64% A(H3N2), 17% A(H1N1), and 8% B. IVE to prevent hospitalization was 24% (95%CI: −1 to 42) overall, 82% (95%CI: 49 to 93) against influenza B, and 16% (95%CI: −17 to 40) against A(H3N2). No IVE was observed in preventing influenza A(H1N1). IVE was high to prevent influenza B, moderate against A(H3N2) and null against A(H1N1). A lower proportion of influenza B cases may explain the smaller IVE in hospitalized patients than in outpatients. The null IVE against A(H1N1) was consistent with the observed antigenic drift and supports the new composition of the 2023–2024 influenza vaccine.https://www.mdpi.com/2076-393X/11/9/1478influenzainfluenza vaccinecase-control studyvaccine effectivenessrepeated vaccination |
| spellingShingle | Iván Martínez-Baz Miguel Fernández-Huerta Ana Navascués Francisco Pozo Camino Trobajo-Sanmartín Itziar Casado Aitziber Echeverria Carmen Ezpeleta Jesús Castilla Influenza Vaccine Effectiveness in Preventing Laboratory-Confirmed Influenza Cases and Hospitalizations in Navarre, Spain, 2022–2023 Vaccines influenza influenza vaccine case-control study vaccine effectiveness repeated vaccination |
| title | Influenza Vaccine Effectiveness in Preventing Laboratory-Confirmed Influenza Cases and Hospitalizations in Navarre, Spain, 2022–2023 |
| title_full | Influenza Vaccine Effectiveness in Preventing Laboratory-Confirmed Influenza Cases and Hospitalizations in Navarre, Spain, 2022–2023 |
| title_fullStr | Influenza Vaccine Effectiveness in Preventing Laboratory-Confirmed Influenza Cases and Hospitalizations in Navarre, Spain, 2022–2023 |
| title_full_unstemmed | Influenza Vaccine Effectiveness in Preventing Laboratory-Confirmed Influenza Cases and Hospitalizations in Navarre, Spain, 2022–2023 |
| title_short | Influenza Vaccine Effectiveness in Preventing Laboratory-Confirmed Influenza Cases and Hospitalizations in Navarre, Spain, 2022–2023 |
| title_sort | influenza vaccine effectiveness in preventing laboratory confirmed influenza cases and hospitalizations in navarre spain 2022 2023 |
| topic | influenza influenza vaccine case-control study vaccine effectiveness repeated vaccination |
| url | https://www.mdpi.com/2076-393X/11/9/1478 |
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