tetano
Editor, Senior Moderator
Vaccine
. 2025 Dec 5:71:128040.
doi: 10.1016/j.vaccine.2025.128040. Online ahead of print. Population effects of influenza vaccination in children and adolescents: Systematic review
Mona Askar[SUP] 1 [/SUP], Karam Adel[SUP] 2 [/SUP], Madeleine Batke[SUP] 1 [/SUP], Yuan Chi[SUP] 3 [/SUP], Lea Gorenflo[SUP] 4 [/SUP], Anna Hayman Robertson[SUP] 5 [/SUP], Kari Johansen[SUP] 6 [/SUP], Jorgen de Jonge[SUP] 7 [/SUP], Philipp Kapp[SUP] 4 [/SUP], Tyra Grove Krause[SUP] 8 [/SUP], Elizabeth Lynch[SUP] 1 [/SUP], Joerg J Meerpohl[SUP] 9 [/SUP], Angeliki Melidou[SUP] 2 [/SUP], Hanna Nohynek[SUP] 10 [/SUP], Carmen Olmedo[SUP] 11 [/SUP], Kate Olsson[SUP] 2 [/SUP], Ioanna Pavlopoulou[SUP] 12 [/SUP], Jaime Jesús Pérez[SUP] 13 [/SUP], Vanessa Piechotta[SUP] 1 [/SUP], Catalina Hamon Pinilla[SUP] 1 [/SUP], Johanna Rubin[SUP] 6 [/SUP], Veronika Učakar[SUP] 14 [/SUP], Julia Wilhelm[SUP] 1 [/SUP], Ole Wichmann[SUP] 1 [/SUP], Thomas Harder[SUP] 15 [/SUP]
Affiliations
Objectives: To investigate indirect vaccine effectiveness (indirVE) of vaccination of children and adolescents with seasonal influenza vaccines against influenza-related outcomes occurring in other population groups.
Methods: We performed a systematic review of studies (randomized and non-randomized) on indirVE of vaccination of participants aged 6 months-17 years with tri- or quadrivalent seasonal influenza vaccines against influenza (lab-confirmed; non-lab-confirmed) occurring in contacts of vaccinated persons or members of the wider community (last search: 17th March 2024). GRADE certainty of evidence (CoE) was evaluated (PROSPERO: CRD42024546400).
Results: We identified 28 studies (5 randomized; 23 non-randomized). In community-based studies, indirect protection against laboratory-confirmed influenza (LCI) ranged from -38 % [95 % CI: -574 to 72] to 61 % [95 % CI: 8-83] (very low CoE). In household-based settings, indirVE against LCI varied between -151.2 % [95 % CI: -1194.6 to 51.3] and 39.4 % [95 % CI: 7.4 to 60.3] (very low CoE). In school-based settings, highly variable indirect effects were observed on LCI, hospitalization, emergency department visits and school/work absenteeism (very low CoE).
Conclusions: There is no clear evidence of indirect effects from influenza vaccination in children. While plausible, effect size is uncertain and varies by study design, population, and vaccine type. Stronger indirect effects appeared only when direct VE was high.
Keywords: Adolescents; Children; Indirect effects; Influenza vaccination; Systematic review.
. 2025 Dec 5:71:128040.
doi: 10.1016/j.vaccine.2025.128040. Online ahead of print. Population effects of influenza vaccination in children and adolescents: Systematic review
Mona Askar[SUP] 1 [/SUP], Karam Adel[SUP] 2 [/SUP], Madeleine Batke[SUP] 1 [/SUP], Yuan Chi[SUP] 3 [/SUP], Lea Gorenflo[SUP] 4 [/SUP], Anna Hayman Robertson[SUP] 5 [/SUP], Kari Johansen[SUP] 6 [/SUP], Jorgen de Jonge[SUP] 7 [/SUP], Philipp Kapp[SUP] 4 [/SUP], Tyra Grove Krause[SUP] 8 [/SUP], Elizabeth Lynch[SUP] 1 [/SUP], Joerg J Meerpohl[SUP] 9 [/SUP], Angeliki Melidou[SUP] 2 [/SUP], Hanna Nohynek[SUP] 10 [/SUP], Carmen Olmedo[SUP] 11 [/SUP], Kate Olsson[SUP] 2 [/SUP], Ioanna Pavlopoulou[SUP] 12 [/SUP], Jaime Jesús Pérez[SUP] 13 [/SUP], Vanessa Piechotta[SUP] 1 [/SUP], Catalina Hamon Pinilla[SUP] 1 [/SUP], Johanna Rubin[SUP] 6 [/SUP], Veronika Učakar[SUP] 14 [/SUP], Julia Wilhelm[SUP] 1 [/SUP], Ole Wichmann[SUP] 1 [/SUP], Thomas Harder[SUP] 15 [/SUP]
Affiliations
- PMID: 41352220
- DOI: 10.1016/j.vaccine.2025.128040
Objectives: To investigate indirect vaccine effectiveness (indirVE) of vaccination of children and adolescents with seasonal influenza vaccines against influenza-related outcomes occurring in other population groups.
Methods: We performed a systematic review of studies (randomized and non-randomized) on indirVE of vaccination of participants aged 6 months-17 years with tri- or quadrivalent seasonal influenza vaccines against influenza (lab-confirmed; non-lab-confirmed) occurring in contacts of vaccinated persons or members of the wider community (last search: 17th March 2024). GRADE certainty of evidence (CoE) was evaluated (PROSPERO: CRD42024546400).
Results: We identified 28 studies (5 randomized; 23 non-randomized). In community-based studies, indirect protection against laboratory-confirmed influenza (LCI) ranged from -38 % [95 % CI: -574 to 72] to 61 % [95 % CI: 8-83] (very low CoE). In household-based settings, indirVE against LCI varied between -151.2 % [95 % CI: -1194.6 to 51.3] and 39.4 % [95 % CI: 7.4 to 60.3] (very low CoE). In school-based settings, highly variable indirect effects were observed on LCI, hospitalization, emergency department visits and school/work absenteeism (very low CoE).
Conclusions: There is no clear evidence of indirect effects from influenza vaccination in children. While plausible, effect size is uncertain and varies by study design, population, and vaccine type. Stronger indirect effects appeared only when direct VE was high.
Keywords: Adolescents; Children; Indirect effects; Influenza vaccination; Systematic review.