Figure 3. Absolute risk difference in mortality among patients who received early versus late treatment with convalescent blood products. Results favor treatment with convalescent blood products (z = 6.50; P < 0.001), and there was no statistical evidence of heterogeneity (Q = 2.76; I² = 0%; P = 0.43). The pooled estimate should be interpreted with caution and should not be generalized to other strains of virulent influenza without further study. *The treatment day of a fatal case could not be determined and was excluded from analysis of early versus late treatment (19, 20). Percentages have been rounded to the nearest whole integer.