Ferrets are not protected against highly pathogenic H7N9 after TVV+MM vaccination.

<p>Groups of 7–8 ferrets received two intramuscular injections with TVV, TVV+MM, PBS, PBS+MM or inactivated H7N9 virus as positive control (Control). 4 weeks later the animals were challenged with a sub-lethal dose of 10^5.5 TCID₅₀ of influenza A H7N9 A/Anhui/1/2013. Ferrets were monitored for 4 consecutive days and sacrificed at day 4 post challenge. (A) Infectious viral load in lung tissue (B) infectious throat viral load (day 1 to 4), (C) percentage of body weight change during the observation period (D) lung weight as determined after sacrifice. Dots indicate individual animals and horizontal lines represent group means (A and D). Lines represent group mean with 95% confidence interval (B) or the interquartile range (C). Asterisks indicate statistically significant differences compared to PBS injected animals (*<i>p</i><0.05, **<i>p</i><0.01, ***<i>p</i><0.001, according to the materials and methods section).