Seeing is believing: A Close-up of the Bifurcated Needle

January 2, 2017

Jet injectors were once used to administer smallpox vaccinations. Although with the invention of the bifurcated needle, administration of smallpox vaccine became simpler, faster, and more practical than with jet injectors.

Fenner and colleagues (1988) wrote,

A few disadvantages of jet injectors emerged during the campaigns in which they were used. In contrast to the simplicity of bifurcated needles, the jet injector required meticulous care and maintenance and considerable repair skills, which could not always be provided despite all the efforts to prepare a detailed, profusely illustrated manual.

As shown in the diagram below, bifurcated needles consisted of a forked-end. In between the forks, or prongs, held a droplet of smallpox vaccine. The vaccinator would perform the multi-puncture technique by pricking the skin with the ends of the prong. The technique consisted of pricking the skin 15 times within a small circular area.


(WHO, 1968)

During the smallpox eradication campaign of the 1960s and 1970s bifurcated needles were reused. Sterilization of the needles were performed by placing 100 needles into a specialized plastic container which would then be submerged into boiling water. Holes in the bottom of the container would let-out the water (Fenner et al., 1988).

Both the jet injector and bifurcated needle have been implicated in spreading the hepatitis C virus amongst those who received smallpox vaccinations in Pakistan. “These results suggest that the widespread prevalence of hepatitis C infection in Pakistan may be an unintended consequence of the country’s smallpox vaccination program” (Aslam, 2005).

Weniger, Jones and Chen (2008) concluded, “Some iatrogenic infections with HBV likely occurred in countries where unsafe MUNJIs [Multiple-use Nozzle Jet Injectors] and unsterile BNs [Bifurcated Needles] were used.”
Statistical analyses and professional opinions by leading experts carry a lot of evidentiary weight. Although photographic evidence creates a new perspective to understanding.

Seeing is believing! These close-up images of the bifurcated needle magnify the reality that this instrument could have easily became infected with blood-borne pathogens.

Here is the Bifurcated Needle.
The tip of a bifurcated needle used to vaccinate individuals wit

Here is the Bifurcated Needle with smallpox vaccine between the prongs.
Close up of the tip of a bifurcated needle used to vaccinate ind

Here the image is magnified 41 times.

Roughened surface at the tip of a bifurcated smallpox vaccinatio
When magnified 187 times, striations in the metal emerge. Crevices appear within the prong area.
Oughened surface at the tip of one of the prongs of a bifurcated

When magnified 747 times, the bifurcated needle appears to be a completely foreign object. The metal appears porous. Ridges and valleys emerge within the prong area.
Roughened surface at the tip of one of the prongs of a bifurcate
Now is it so hard to imagine blood or viruses getting within these porous regions or getting attached upon the sharp microscopic ridges of the metal?

Today, bifurcated needles are still used in administering smallpox vaccine. Although now they are intended to be single-use, disposable needles. One needle, one patient.

Hmm…if only the jet injector nozzle was also photographed with a magnifying camera.


Photos are courtesy of and are published under public domain.


  • (Aslam et al., 2005) Aslam M, Aslam J, Mitchell BD, Munir KM. “Association Between Smallpox Vaccination and Hepatitis C Antibody Positive Serology in Pakistan Volunteers.” Journal of Clinical Gastroenterology. 2005 Mar;39(3):243-6.
  • (Fenner et al., 1988) Fenner F, Henderson DA, Arita I, Je〉ek Z, Ladnyi ID. Smallpox and its Eradication, Geneva: World Health Organization, 1988 (ISBN 92 4 156110 6).Available at:
  • (Weniger, Jones, & Chen, 2008) Weniger BC, Jones TS, & Chen RT. The Unintended Consequences of Vaccine Delivery Devices Used to Eradicate Smallpox: Lessons for Evaluating Future Vaccination Methods. 2008.
  • (WHO, 1968) World Health Organization. Instructions for smallpox vaccination with bifurcated needle. World Health Organization, Geneva. 1968. Available at:

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