tetano
Editor, Senior Moderator
Int J Infect Dis
. 2024 Dec 16:107364.
doi: 10.1016/j.ijid.2024.107364. Online ahead of print. Effectiveness of influenza vaccination in preventing confirmed influenza cases and hospitalizations in Northern Spain, 2023/24 season: A population-based test-negative case-control study
Iván Martínez-Baz[SUP] 1 [/SUP], Ana Navascués[SUP] 2 [/SUP], Camino Trobajo-Sanmartín[SUP] 3 [/SUP], Francisco Pozo[SUP] 4 [/SUP], Miguel Fernández-Huerta[SUP] 2 [/SUP], Maddi Olazabal-Arruiz[SUP] 2 [/SUP], Lucía Argente-Colas[SUP] 2 [/SUP], Guillermo Ezpeleta[SUP] 5 [/SUP], Aitziber Echeverria[SUP] 3 [/SUP], Itziar Casado[SUP] 3 [/SUP], Carmen Ezpeleta[SUP] 2 [/SUP], Jesús Castilla[SUP] 3 [/SUP]
Affiliations
Objective: We estimated the influenza vaccination effectiveness (IVE) in preventing medical consultations and hospitalizations due to influenza during the 2023/24 season.
Methods: Two test-negative case-control studies analyzed patients who consulted primary healthcare or were hospitalized for respiratory symptoms and were tested for influenza by PCR in the 2023/24 season in Navarre, Spain. Influenza vaccination status in the current and previous seasons was compared between confirmed influenza cases and test-negative controls. IVE was calculated as (1-adjusted odds ratio)x100.
Results: Of 3133 hospitalized patients, 529 (17%) were positive for influenza: 71% A/H1N1, 23% A/H3N2, and 7% A non-subtyped. IVE to prevent hospitalizations was 43% (95%CI: 26-56%) overall, 61% (95%CI: 32-77%) in people younger than 65 years old and 35% (95%CI: 10-53%) in older people. IVE was 48% (95%CI: 30-61%) against influenza A/H1N1, and 15% (95%CI: -42-49%) against influenza A/H3N2. IVE in people vaccinated only in the previous season was 28% (95%CI: -5-51%). Among 417 outpatients, 146 (35%) were confirmed for influenza. IVE to prevent outpatient cases was 49% (95%CI: -9-76%) overall and 42% (95%CI: -33-74%) against influenza A/H1N1.
Conclusions: IVE was moderate against influenza A/H1N1 and low against influenza A/H3N2 in the 2023/24 season.
Keywords: case-control study; influenza; influenza vaccine; previous vaccination; vaccine effectiveness.
. 2024 Dec 16:107364.
doi: 10.1016/j.ijid.2024.107364. Online ahead of print. Effectiveness of influenza vaccination in preventing confirmed influenza cases and hospitalizations in Northern Spain, 2023/24 season: A population-based test-negative case-control study
Iván Martínez-Baz[SUP] 1 [/SUP], Ana Navascués[SUP] 2 [/SUP], Camino Trobajo-Sanmartín[SUP] 3 [/SUP], Francisco Pozo[SUP] 4 [/SUP], Miguel Fernández-Huerta[SUP] 2 [/SUP], Maddi Olazabal-Arruiz[SUP] 2 [/SUP], Lucía Argente-Colas[SUP] 2 [/SUP], Guillermo Ezpeleta[SUP] 5 [/SUP], Aitziber Echeverria[SUP] 3 [/SUP], Itziar Casado[SUP] 3 [/SUP], Carmen Ezpeleta[SUP] 2 [/SUP], Jesús Castilla[SUP] 3 [/SUP]
Affiliations
- PMID: 39694231
- DOI: 10.1016/j.ijid.2024.107364
Objective: We estimated the influenza vaccination effectiveness (IVE) in preventing medical consultations and hospitalizations due to influenza during the 2023/24 season.
Methods: Two test-negative case-control studies analyzed patients who consulted primary healthcare or were hospitalized for respiratory symptoms and were tested for influenza by PCR in the 2023/24 season in Navarre, Spain. Influenza vaccination status in the current and previous seasons was compared between confirmed influenza cases and test-negative controls. IVE was calculated as (1-adjusted odds ratio)x100.
Results: Of 3133 hospitalized patients, 529 (17%) were positive for influenza: 71% A/H1N1, 23% A/H3N2, and 7% A non-subtyped. IVE to prevent hospitalizations was 43% (95%CI: 26-56%) overall, 61% (95%CI: 32-77%) in people younger than 65 years old and 35% (95%CI: 10-53%) in older people. IVE was 48% (95%CI: 30-61%) against influenza A/H1N1, and 15% (95%CI: -42-49%) against influenza A/H3N2. IVE in people vaccinated only in the previous season was 28% (95%CI: -5-51%). Among 417 outpatients, 146 (35%) were confirmed for influenza. IVE to prevent outpatient cases was 49% (95%CI: -9-76%) overall and 42% (95%CI: -33-74%) against influenza A/H1N1.
Conclusions: IVE was moderate against influenza A/H1N1 and low against influenza A/H3N2 in the 2023/24 season.
Keywords: case-control study; influenza; influenza vaccine; previous vaccination; vaccine effectiveness.