Fig. 5

Lung viral loads and weight loss after challenge. Aged BALB/c mice (18–22 months) lungs were collected at 3 days post-infection after sub-lethal challenge with H1N1 A/California/07/2009. Three days post-infection a lung viral loads were measured and throughout the infection mice were closely monitored for b weight loss. a is representative of 3–5 mice/group from two studies and b are representative of 5–10 mice/group combined from two studies. For statistical analysis, a One-way ANOVA was performed on the log10 values of the viral titres and the Tukey’s multiple comparison test was performed. For b Two-way ANOVA followed by the Tukey’s multiple comparison test (**** p < 0.0001, *** p 0.001, ** p < 0.01, * p < 0.05) (see Additional file 1: Table S2). Error bars represent the standard error of the mean