Folks have already pointed out the whole "multiple teams of sled dogs" thing.
The dogs also weren't delivering vaccine. They were delivering diphtheria antitoxin, which is a treatment for diphtheria, not an inoculation. The kids were already sick.
There was technically a vaccine for diphtheria then (it was invented in 1923, two years before this epidemic), but it wouldn't have saved anyone who'd already caught the infection.
Folks have already pointed out the whole "multiple teams of sled dogs" thing.
The dogs also weren't delivering vaccine. They were delivering diphtheria antitoxin, which is a treatment for diphtheria, not an inoculation. The kids were already sick.
There was technically a vaccine for diphtheria then (it was invented in 1923, two years before this epidemic), but it wouldn't have saved anyone who'd already caught the infection.