AUTHOR=Prins Manon L. M. , van Dokkum Ernst D. , de Vries Aiko P. J. , Tushuizen Maarten E. , van der Helm Danny , Spithoven Edwin M. , van der Meer Irene M. , Groeneveld J.H. Marc , Visser Leo G. , le Cessie Saskia , Vollaard Albert M. , Groeneveld Geert H. 

TITLE=A Retrospective Test-Negative Case-Control Study to Evaluate Influenza Vaccine Effectiveness in Preventing Influenza Among Immunocompromised Adults With a Solid Organ Transplant

JOURNAL=Transplant International

VOLUME=Volume 38 - 2025

YEAR=2025

URL=https://www.frontierspartnerships.org/journals/transplant-international/articles/10.3389/ti.2025.14187

DOI=10.3389/ti.2025.14187

ISSN=1432-2277

ABSTRACT=Vaccination may prevent influenza in solid organ transplant (SOT) recipients. This study evaluates the influenza vaccine effectiveness (VE) in this high-risk population in the Netherlands. We also compared disease progression and 30-day mortality between vaccinated and unvaccinated influenza patients. In this multicenter, test-negative case-control study, SOT recipients with respiratory symptoms were included when tested for viral respiratory infections during the respiratory seasons between January 1, 2013 and July 1, 2024. Cases had a positive influenza PCR, while controls tested negative. Influenza vaccination in cases (74/174) and controls (291/602) were compared after adjusting for potential confounders. VE was calculated as (1-adjusted odds ratio) x 100. The overall VE was 6.9% (95% CI -40.9 to 38.4), with considerable variation across seasons. For those aged ≥65 years, VE was higher (32.4%, 95% CI -56.5 to 70.8) compared to those aged 18-64 years (4.8%, 95% CI -56.5 to 42.1). The adjusted VE against influenza A (6.2% (-48 to 40.5)) was higher than against influenza B (-3.8% (-146.7 to 56.3)). No differences in influenza-related complications were observed between the vaccinated and unvaccinated cases. The observed seasonal influenza vaccine effectiveness in adult SOT recipients is limited; further investigation for improvement is warranted.