Fig 4.
A/Philippines (H3N2) live virus challenge. Four weeks after the last immunization, 6 mice of each group were infected i.n. with 5 LD50s of mouse-adapted A/Philippines viruses (250 PFU). Survival of mouse groups immunized i.m. (A) or i.n. (B) and body weight changes of i.m. (C) and i.n. (D) groups were monitored and recorded for 15 days to indicate the protective efficacy of the vaccines. In panels C and D, the data represent means of the body weight change (percentage of prechallenge body weight) of 6 mice in each group.