Survival benefits of post-exposure vaccination. Kaplan–Meier survival curves are shown for animals challenged with 170× LD50 dose and vaccinated on Day 1 (A) or Day 3 (B) postexposure with Dryvax® (white squares), ACAM2000® (black squares), IMVAMUNE® (black triangles), or PBS (gray circles). Animals challenged with a 2× LD50 dose of MPXV and vaccinated 1 (C) or 3 (D) days postexposure with ACAM2000® (black squares), IMVAMUNE® (black triangles), or unvaccinated (gray circles) are also shown. Fractions represent the cumulative number of animals censored at each time-point over the total numbers of animals in each group. Some symbols are sized differently for clarity of superimposed data. When compared to the unvaccinated control survival curve, none of the vaccinated survival curves showed statistically significant differences by log-rank (Mantel–Cox) test (p > 0.05).