TABLE 4.

Protection against viral infection after intranasal vaccination with 105/NE or scarification with live VVWRa

Challenge dose (PFU)LD50cProtectionb
NE vaccineScarificationControl
1.0E+07770/53/50/5
2.0E+06150/55/50/5
4.0E+0531/55/50/5
8.0E+040.622/55/50/5
1.6E+040.124/55/50/5
3.2E+030.025/55/55/5
  • a Protection against viral infection was assessed for mice vaccinated with three doses of NE-killed vaccine (105/NE) compared to a single scarification with 105 PFU live VVWR. Viral challenge was performed at 12 weeks after initial vaccination. Mice were observed twice daily for changes in body weight and core body temperature after challenge with live virus. Significantly more changes in body weight and temperature were observed for the VV/NE-immunized animals than for those immunized with scarification, especially at higher virus challenge doses (P > 0.5).

  • b Presented as a ratio of mice which did not have decreased body weight or temperature at any time after challenge to all mice.

  • c Calculated value for 1× LD50 was 1.3 × 105 PFU of VVWR.