Convalescent Plasma Treatment Reduced Mortality in Patients With Severe Pandemic Influenza A (H1N1) 2009 Virus Infection

Experience from treating patients with Spanish influenza and influenza A(H5N1) suggested that convalescent plasma therapy might be beneficial. However, its efficacy in patients with severe pandemic influenza A(H1N1) 2009 virus (H1N1 2009) infection remained unknown.

During the period from 1 September 2009 through 30 June 2010, we conducted a prospective cohort study by recruiting patients aged ≥ 18 years with severe H1N1 2009 infection requiring intensive care. Patients were offered treatment with convalescent plasma with a neutralizing antibody titer of ≥ 1:160, harvested by apheresis from patients recovering from H1N1 2009 infection. Clinical outcome was compared with that of patients who declined plasma treatment as the untreated controls.