Population
Patients hospitalized with severe influenza (5 studies, n= 598).
Intervention
Convalescent plasma or hyperimmune intravenous immunoglobulin (H-IVIG).
Comparison
Various comparators (normal intravenous immunoglobulin, standard care, low-titre anti-influenza, placebo).
Outcome
Pooled analyses yielded no evidence that using convalescent plasma to treat severe influenza resulted in significant reductions in mortality, number of days in the intensive care unit, or number of days on mechanical ventilation.