Davey RT, Fernández-Cruz E, Markowitz N, et al. - Researchers undertook this randomised, double-blind, placebo-controlled trial in 45 hospitals in Argentina, Australia, Denmark, Greece, Mexico, Spain, Thailand, UK, and the USA over five influenza seasons from 2013–14 to 2017–18, to determine whether anti-influenza hyperimmune intravenous immunoglobulin (hIVIG) affords a safe and effective option for adults with influenza A or B infection. In a randomized manner, they allocated (1:1) adults (≥ 18 years of age) who were admitted for hospital treatment with laboratory-confirmed influenza A or B infection to receive standard care plus either a single 500-mL infusion of high-titre hIVIG (0·25 g/kg bodyweight, 24·75 g maximum; hIVIG group) or saline placebo (placebo group). Findings revealed no superiority of hIVIG over placebo, when delivered alongside standard care (most commonly oseltamivir), in adults hospitalised with influenza infection. The observed effect of hIVIG was opposite in contrast to prespecified subgroup hypothesis that more favourable responses in patients with influenza A vs B would be achieved using hIVIG. Antibody affinity analyses supported the clinical advantage of hIVIG for patients with influenza B, though confirmation is justified.