A late sharp increase in influenza detections and low interim vaccine effectiveness against the circulating A(H3N2) strain, Denmark, 2021/22 influenza season up to 25 March 2022
Hanne‐Dorthe Emborg, Lasse S. Vestergaard, Amanda Bolt Botnen, Jens Nielsen, Tyra Grove Krause, Ramona Trebbien
Abstract
We estimated interim influenza A vaccine effectiveness (VE) following a late sharp rise in cases during an influenza A(H3N2)-dominated 2021/22 season, after lifting COVID-19 restrictions. In children aged 2-6 years offered a live attenuated influenza vaccine, adjusted VE was 62.7% (95% CI: 10.9-84.4) in hospitalised and 64.2% (95% CI: 50.5-74.1) in non-hospitalised children. In non-hospitalised patients aged 7-44 years, VE was 24.8% (95% CI: 12.8-35.2); VE was non-significant in remaining age groups and hospital/non-hospital settings.
Topics & Concepts
InterimMedicineInfluenza vaccineInfluenza seasonCoronavirus disease 2019 (COVID-19)Strain (injury)VirologyLive attenuated influenza vaccinePediatricsSeasonal influenzaInterim analysisInternal medicineVaccinationEmergency medicineRandomized controlled trialArchaeologyInfectious disease (medical specialty)DiseaseHistoryInfluenza Virus Research StudiesRespiratory viral infections researchBacterial Infections and Vaccines