Observational studyBMC infectious diseases2026
Hospitalized children with influenza virus: a 17 year-long observational study including the 2009 H1N1 influenza pandemic and COVID-19 pandemic.
Observational study in BMC infectious diseases, 2026. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 1 paper.
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The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.
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Who cites it
1 citing paper in PubMed.
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Authors and funding
6 authors.
Funding
No grant is acknowledged in the PubMed record.
Abstract
backgroundInfluenza viruses (IFV) have major impacts on children's health. We studied IFV A/B epidemiology and disease severity during a 17 year-long period including the 2009 H1N1 influenza pandemic and post-COVID-19 in 2021-2023.
methodsNasopharyngeal samples from children referred with fever or respiratory symptoms to a Norwegian hospital from 2006 to 2023 were tested with PCR for IFV A/B and 17 other pathogens. We compared IFV hospitalization rates and disease severity before and during the 2009 influenza pandemic, and before and after the COVID-19 pandemic, respectively, using age-adjusted logistic regression analyses.
resultsFrom 2006 to 2023, 502 children with IFV A/B were included (IFV A 74%, IFV B 26%). Two-hundred-fifty-one (50%) were hospitalized > 24 h. During the 2009 H1N1 influenza pandemic rates of hospitalization > 24 h in children ≤ 5 and > 5 years of age increased from 44 to 72, and 4 to 20 per 100,000, respectively, compared to 2006-2009. The median age of IFV positive children doubled from 23 to 49 months (p=.006), but no other clinical changes occurred. Post-COVID-19 (2021-2023), the hospitalization rates only increased in children > 5 years from 12 to 25 per 100,000, and the median age almost doubled from 33 to 62 months (p<.001) compared to 2010-2020. Post-COVID-19, fewer children had lower respiratory tract infections (aOR 0.32, 95% CI 0.20-0.53) and severe complications (aOR 0.24, 95% CI 0.07-0.82).
conclusionsCompared to other influenza seasons, disease severity during the 2009 H1N1 influenza pandemic was unchanged, but post-COVID-19 children referred to hospital with IFV A/B had milder disease.
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