Figure 2.

Live challenge with wild-type B/Florida/4/2006 and B/Phuket/3073/2013. (A) TCID₅₀ values for each strain used for initial passage infection. Values shown are an average of three independent experiments with error bars representing standard deviation between three independent replicates. Statistical significance was determined through unpaired t-test, ** p < 0.01; (B) Weight loss over 14 days shown after i.n. infection with 1:2 dilution of allantoic fluid of each parent virus. A ≥25% initial weight lost (dotted line) was used as a threshold for humane sacrifice of the animals.