Fig. 4.

Protective efficacy of recombinant vaccinia virus containing NP and M2e genes against 20 MLD50 of PR8. Five groups of mice were immunized with recombinant vaccinia viruses and challenged with 20 MLD50 of influenza virus strain PR8. Among them, mice immunized with recombinant vaccinia virus RVJ1175 served as vector control. Mice were monitored daily for 21 days after PR8 challenge. A Mice were weighed daily to monitor morbidity. Average weights in each treatment group were followed for the duration of the study, and the percentage of the original body weight was calculated based on the average starting weight for each group at day 0. B Survival rates were calculated and compared among groups. ns not significant, *P < 0.05; **P < 0.01; ***P < 0.001.