A special type of needle used specifically to deliver smallpox vaccine. It has two small prongs on the end, and it’s just deep enough to puncture the skin multiple times and deliver the vaccine to the correct depth. It was used heavily in the worldwide campaign to eradicate smallpox in the 1960s and 1970s.
After 9/11, bifurcated needles were once again manufactured in case of biological terrorist attacks. Since they only need to penetrate the skin to a shallow depth, they can be clean and re-used, which would be valuable in the event of a mass vaccination event.
Why I Looked It Up
A book about life expectancy discussed the bifurcated needle as a technological advance that made smallpox the only disease ever eradicated in humans.