How the coronavirus vaccine development compares to other shots in history

The invention of the bifurcated needle allowed more efficient vaccine delivery.
Carol Smiljan/NurPhoto via Getty Images
Vaccine research and development has improved massively throughout history.
Nearly 200 years passed between the creation of the first successful vaccine and the eventual eradication of smallpox.
The influenza virus was isolated in a lab in 1933, and the first flu vaccine wasn't licensed until 1945.
Coronavirus vaccine research began just a few months after the first case of CO