Military Jet Injectors: Press-O-Jet

Jet Infectors - Press-O-Jet

Background Info
The Press-O-Jet was the first high-speed multi-use nozzle jet injector ever to be developed. The device was developed by researchers at Walter Reed Army Institute of Research in collaboration with Z & W Manufacturing Company of Wickliffe, Ohio. Z & W patented the Press-O-Jet in 1952. Sometime thereafter Press-O-Jet was acquired by the Scientific Equipment Manufacturing Corporation of Larchmont, New York. In 1965, the device was sold-off to the Parker Hanifin Corporation (

Press-O-Jet was used amongst both military and civilian populations between 1952 and the early 1960s.

Military Usage
Multi-use nozzle jet injectors were invented at the request of the U.S. Armed Forces. Around 1951, the Armed Forces Epidemiological Board’s Commission on Immunization requested the Army Medical Service Graduate School to develop “jet injection equipment specifically intended for rapid semiautomatic operation in large-scale immunization programs” (Warren et al., 1955). Within the following year the Graduate School developed a series of models. Between 1952 and 1954, researchers at Walter Reed Army Institute of Research and Z&W Manufacturing Company had constructed a working prototype, known as the Press-O-Jet.

During the Press-O-Jet’s clinical testing, it was widely used on military personnel. A review of the literature found in 1954, 1,685 soldiers at Fort Meade and in the Military District of Washington, D.C. received a typhoid vaccination (Star-Democrat, 1954; Warren et al., 1955), and another 1000 recruits stationed at Fort Knox were vaccinated for smallpox with the Press-O-Jet (Elisberg et al., 1956). From 1955 to 1956, the Press-O-Jet administered 20,145 influenza vaccinations at Naval Air Station at Norfolk (Anderson et al., 1958). The scientific literature also vaguely noted the Press-O-Jet administered 1,440 influenza vaccinations to military personnel (Benenson, 1959).

Numerous photographs and newspaper articles have documented the Press-O-Jet being used within the U.S. Armed Forces. These photos, provided by the National Archives and Records Administration, show the Press-O-Jet being utilized within the military in 1955.

Jet Infectors - Press-O-Jet NARA (a)
(National Archives and Record Administration photo no. 366-P5-55-3318).

Jet Infectors - Press-O-Jet NARA (b)
(National Archives and Record Administration photo no. 306-P5-55-3313).

The caption on the backside of these images reads:

Wash., D.C. A new needle-less, automatic, multiple-dose jet “gun” for mass vaccine injections is being tested at Walter Reed Army Medical Center. The new inoculation mechanism gives promise that someday the Army’s soldier’s may receive quick and practically painless inoculation. Here Army doctor sided by Army nurse inoculates a soldier with the inoculation “gun” as other soldiers wait their turn. Source: Intern’l News S1276260 2/20/55 copy msg”.

In 1954, Walter Reed Medical Center tested the Press-O-Jet upon military personnel as documented in this newspaper article. (Star-Democrat. Painless Shot. 28th May 1954. pg. 35)

Jet Infectors - Star Democrat - Press-O-Jet

In this photograph, the Press-O-Jet was tested on patients at the Bacteriology Research Laboratory within the Armed Forces Institute of Pathology around 1955. (NCP 013106-13) (Otis Historical Archives, National Museum of Health and Medicine, Silver Spring, Maryland)

Jet Infectors - Press-O-Jet Bacteriology Research Laboratory

This newspaper article, captured below, reveals the Press-O-Jet was developed by Dr. Joel Warren and his colleagues within the United States Army and tested upon military inductees.

Rome News Tribune, Rome, Georgia
February 18, 1955

New Vaccine “Jet Gun” May Replace Needles

CHICAGO (INS)—“Watch the needle,” the familiar cry of inductees to their buddies as they lined up for vaccination shots, may soon take its place in military history alongside the out-dated “man the halyards” and “saddle up.”

Four United States Army Researchers have developed a needleless automatic, multiple-dose jet “gun” for mass vaccine injections at induction centers and embarkation points.

They claim their injector, which operates with an automatic cocking device like a machine gun, although not completely painless, hurts considerably less than the old-style “needle-with-an-outboard-motor-on-it” of World War II fame.

The researchers say “in an appreciable number of cases, persons report no pain at all.”

Writing in the current journal of the American Medical Assn, published in Chicago, Dr. Joel Warren of Walter Reed Army Medical Center in Washington, describes how the needle-free gun shoots a tiny jet of vaccine right through the skin under some 250 pounds of pressure.

The pressure comes from a spring-driven piston pump. Each injection takes about one second.

After the operator triggers off each “shot,” a hydraulic pump re-cocks the gun. Since no needle is used there is no need for sterilization after each shot.
In trial runs, a total of 1,685 Army inductees were vaccinated daily with the US Army’s standard triple typhoid vaccine.

Each inductee got a jet injection in one arm and a regular needle tetanus injection in the other arm at the same time administered by a “highly-trained” corpsman.

The report concluded the trial “substantiated” hopes that jet injection is “a promising procedure potentially useful in many military and civilian situations that require immunization or medication of large numbers of people in a short time.”

Dr. Warren was joined by Frank Ziberl, Arthur Kish and Louis Ziherl, all of Cleveland, in the gun development.

Presently, the National Museum of Health and Medicine, formerly known as the Army Medical Museum, proudly displays the Press-O-Jet within their military medical exhibit. The caption below the display reads, “By the Vietnam War, injectors distributed vaccines and medications on a large scale. The Walter Reed Army Institute of Research prototyped this example.”

Jet Infectors - Press-O-Jet Museum Display

Research Documented Presence of Blood & Risk of Hepatitis
Numerous scientific studies have documented the presence of blood at the injection site and upon the jet gun nozzle following Press-O-Jet injections. One of these studies, even warned of the risk of transmitting hepatitis within the early days of jet injection.

  • Warren and colleagues (1955) administered the triple typhoid vaccine using the Press-O-Jet to 1,685 Army inductees. Bleeding at the injection site of these military personnel were observed. In several instances the researchers noted the jet stream lacerated the patient’s skin when the proper injection technique was not followed.
  • Lipson and colleagues (1958) found bleeding at the injection site when using the Press-O-Jet injector. Lipson was studying the antibody response after administering the poliomyelitis vaccine by jet injection. He observed after administering two doses of vaccine to 34 children that “there was frequently a small amount of leakage of vaccine from the puncture site in both groups, accompanied occasionally by a small amount of blood.” Moreover, Lipson observed blood on the nozzle of the jet injector in two instances. So out of 68 injections visible contamination of the nozzle occurred two times. This equates to 3 percent of the injections. Lipson wrote, “Although the risk of transmitting the virus of hepatitis is slight, it does exist; and in using this instrument care should be taken to avoid accidental contamination with blood or tissue juices” (emphasis added).
  • Anderson, Lindberg and Hunter (1958) observed a large-scale military field trial conducted upon sailors stationed at Naval Air Station in Norfolk, Virginia. The mass influenza vaccination campaign administered 20,145 injections with a Press-O-Jet injector between 1955 and 1956. Sailors were vaccinated at a rate of 734 injections per hour. The researchers observed bleeding at the injection site of sailors and in several cases the jet stream lacerated sailors’ arms due to an improper injection technique by corpsmen.
  • Following the mass Salk Polio vaccination campaign, which was the first major field-trial of jet injectors, Dr. Robert Hingson reported jet injectors produced bleeding and ecchymosis at the injection site. The campaign used the Press-O-Jet amongst other jet injector devices (Hingson et al., 1957).
  • Elisberg, McCown and Smadel (1956), who wanted to use jet injectors for mass smallpox vaccinations, assumed “since no needle is used, contamination of the instrument by such blood-borne microbial agents as malaria or serum hepatitis is avoided and frequent sterilization of the jet injection apparatus is unnecessary.” Yet Elisberg, McCown, and Smadel not only observed bleeding following a jet injection, they illogically thought if the device was removed immediately the patients would be safe. Weniger and Papania (2008) reported Elisberg, McCown and Smadel’s study used the Press-O-Jet.

Special thanks to the National Archives and Records Administration for their assistance.


  • (Anderson, Lindberg, & Hunter, 1958) Anderson EA, Lindberg RB, Hunter DH. Report of large-scale field trial of jet injection in immunization for influenza. JAMA 167:549–552, 1958.
  • (Elisberg, McCown, & Smadel, 1956) Elisberg BL, McCown JM, Smadel JE. Vaccination against smallpox. Jet injection of chorio-allantoic membrane vaccine. J Immunol 1956;77(5):340-351.
  • (Hingson et al., 1957) Hingson RA, Davis HS, Bloomfield RA, Brailey RF. Mass inoculation of the Salk polio vaccine with the multiple dose jet injector. GP [General Practice] 15:94–96, 1957.
  • (Lipson et al., 1958) Lipson MJ, Carver DH, Eleff MG, et al. Antibody response to poliomyelitis vaccine administered by jet injection. Am J Public Health 48:599–603, 1958.
  • (Star-Democrat, 1954) Star-Democrat. Painless Shot. 28th May 1954. pg. 35.
  • (Warren et al., 1955) Warren J, Ziherl FA, Kish AW, Ziherl LA. Large scale administration of vaccines by means of an automatic jet injection syringe. JAMA 157:633–637, 1955.
  • (Weniger & Papania, 2008) Weniger BG, Papania MJ. Alternative Vaccine Delivery Methods [Chapter 61]. In: Plotkin SA, Orenstein WA, Offit PA, eds. Vaccines, 5th ed. Philadelphia, PA: Saunders (Elsevier); 2008;1357-1392.

© Jet Infectors, 2016 – 2021
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One thought on “Military Jet Injectors: Press-O-Jet

  1. I have suffered with autoimmune diseases Systemic Lupus fibromyalgia symptoms Myasthenia Gravis and Parkinson’s I almost lost my finger starlet Jackson and was told I wouldn’t be able to be a normal Army mans duti s and they r com nd d I tak an honorable discharge . This variant of jet injection was given to many during The Vietnam era what are the long t rm affects and why did the service ban these jet injection is Thisreport states experiment vaccinations were don to us our troops without consent Anyone else suffered their white led lives with systemic pain since the jeting cations at fort did McGuire AFB or at Fort Jackson or maybe even Huntsville Alabama base Let me know please


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