Survival of BALB/c mice after HK/Syd challenge. Survival of BALB/c mice after HK/Syd challenge. After the quaternary exposure to the vaccine, mice were infected with 10 MLD50 HK/Syd and monitored for morbidity (percent weight loss) (top) and mortality (percent survival) (bottom). Data are reported for the following numbers of mice in the various groups: for vector DNA plus PBS, n = 8; for vector DNA plus GFP-VRP, n = 9; for vector DNA plus HA-VRP, n = 9; for HA-DNA plus PBS, n = 10; for HA-DNA plus GFP-VRP, n = 10; and for HA-DNA plus HA-VRP, n = 11. An asterisk indicates a significant difference in results compared to those for vector DNA-plus-PBS and vector DNA-plus-GFP-VRP groups (P < 0.05 by log rank test of the Kaplan-Meier survival data). Victor C. Huber et al. Clin. Vaccine Immunol. 2006; doi:10.1128/CVI.00156-06