Impact of CDC’s 1993-94 Unpublished Study – Part II

Following Grabowsky and colleagues evaluation of the Ped-O-Jet, officials within the CDC initiated meetings to discuss the risks of multi-use nozzle jet injectors (MUNJI).

1995 CDC / WHO Meeting – Review the Safety of Jet Injectors
In November of 1995, the CDC and World Health Organization (WHO) gathered for a meeting in London titled, Review the Safety of Jet Injectors. Those present were CDC and WHO experts on device safety, vaccine safety, and laboratory testing. Amongst the attendees were Dr. Robert Chen of the CDC, John Lloyd of the WHO, Dr. Peter Hoffman from the United Kingdom’s Public Health Laboratory Service, and a representative from PATH (Fields, 1996). Dr. Chen had previously been involved in CDC’s safety testing of the Med-E-Jet and Ped-O-Jet (Chen).

The goal of this meeting was to rewrite the safety standards for all jet injector devices. CDC and WHO both agreed, the “risk of cross infection must be zero” (PATH, 1996). The CDC explained this “zero tolerance” level means “no contamination should be detectable on any reusable surface of the deice that comes into direct or indirect contact with the patient’s skin” (Fields, 1996). Both agencies agreed for these devices to be attractive to consumers, they should remain “competitive with [the] current price of autodestruct syringes.” Moreover, both agencies recommended that jet injectors should be regulated and undergo testing to ensure safety performance (PATH, 1996).

WHO announced that Dr. Peter Hoffman of the UK’s Public Health Laboratory Service would be overseeing “the design and implementation of a new laboratory safety test to evaluate all injectors against this new standard” of zero tolerance (Fields, 1996).

1996 CDC & WHO Conference – Jet Injectors for Immunization, Current Practice and Safety, Improving Designs for the Future
In October of 1996, members of CDC’s National Immunization Program along with the WHO extended the discussion on jet injectors to include various health agencies, manufacturers, and consumers. The goal of this meeting was for all involved parties to discuss the safety of existing jet injectors and to develop more stringent specifications for the development of a new generation of jet injectors. Amongst the attendees of the meeting were CDC researchers Dr. Robert Chen and Walter Bond, as well as Dr. Glaucus de Souza Brito from the Brazilian Ministry of Health, former Ped-O-Jet CEO Robert Harrington and the current owners of Ped-O-Jet, Keystone Industries.

Walter Bond, who was a part of all three of CDC’s jet injector studies, served as an expert panelist on jet injector safety. “Existing jet injectors, such as Ped-O-Jet,” stated Bond, “are not particularly easy to contaminate, but once they are contaminated, they can indeed transmit disease” (Fields, 1996).

Also during the meeting, the committee identified the need for additional safety testing. “Examining ejectates from Ped-O-Jet vaccinations given to new military recruits in the U.S.…would represent best-use circumstances for the jet injector,” concluded the committee (Fields, 1996). However, in the following year Keystone Industries informed the Department of Defense (DoD) of its intent to withdraw and stop manufacturing the Ped-O-Jet over risk of cross-contamination. Consequently, in December of 1997 DoD stopped using all MUNJI devices, including the Ped-O-Jet. The study, which intended to examine the ejectates of Ped-O-Jet vaccinations from military recruits, was never conducted.

The 1996 joint CDC/WHO meeting also identified several countries had allowed jet injector devices to be grandfathered-in and thus bypass safety regulations.

During the Atlanta meeting in October 1996 it became clear that jet injectors in the United States, U.K., France and Italy had been ‘grandfathered in’ without national regulatory controls. The reason for this appeared to be the long history of use of jet injectors without recorded mishap.

The Food and Drug Administration of the United States informed the Atlanta meeting that they intend to review the status of jet injection devices with a view to develop such regulation in the near future (WHO, 1997).

The following statement was unanimously supported at the CDC/WHO conference. It is an amalgamation of previous CDC statements with an update on ongoing safety trials.

Background information on jet injectors used in immunization

The following statement was unanimously supported at the joint WHO-CDC Meeting on “Jet Injectors for Immunization: Current Practice and Safety” Atlanta 2-4 October 1996.

Jet injectors that use the same nozzle tip to vaccinate more than one person (multiple-use nozzle jet injectors) have been used worldwide since 1952 to administer vaccines when many persons must be vaccinated with the same vaccine within a short time period. These jet injectors have been generally considered safe and effective for delivering vaccines if used properly by trained personnel. However, concerns have been expressed about the potential risk of transmission of bloodborne diseases associated with these devices. In addition, it is known that some immunization campaigns have been conducted with inadequately trained personnel using jet injectors that have been poorly maintained.

Mathematical modeling indicates that the potential risk from properly used jet guns is similar in magnitude to that from properly used needle and syringes, and considerably less than that from improperly used needles and syringes. Use of jet injectors poses very low risk to health care workers delivering the injections and to the public at large.

The multiple use nozzle jet injector most widely used (Ped-O-Jet) has never been implicated in transmission of bloodborne diseases. However, one report of an outbreak of hepatitis B caused by non-compliant use of another type of multiple use nozzle jet injector (Med-E-Jet) in a weight loss clinic, and laboratory studies in which blood contamination of jet injectors has been simulated have caused concern that use of multiple use nozzle jet injectors may pose a risk of bloodborne disease transmission to vaccine recipients. In addition, studies in Brazil with Ped-O-Jet have shown that under field conditions that ejected vaccine was positive for occult blood by urine dipstick testing in 0.2% to 6.6% (1% average) of inoculations. These studies need to be repeated in other areas under varying conditions of use. The potential risk of bloodborne transmission would vary according to the prevalence of bloodborne agents such as hepatitis B, hepatitis C, and HIV in the population, the relative infectivity of each agent, and the susceptibility of the population to the particular pathogen.

Auto-destruct syringes represent the current method of choice for conducting mass immunization campaigns. Multiple-use nozzle jet gun injectors can be used in situations in which large numbers of persons must be rapidly vaccinated with the same vaccine, the use of auto-destruct needles and syringes is not practical, and health authorities judge that the public health benefit from the use of jet injector outweighs the potential risk of blood borne disease transmission. Properly used jet injectors are safer than disposable syringes in situations where the improper disposal and re-use of needles and syringes occurs.

The potential risk from jet injectors can be minimized by training and supervision of health care workers, proper maintenance and cleaning of the device, and thorough wiping of the surface of the injector which contacts the skin with a fresh acetone or alcohol moistened swab following each injection. Manufacturers directions for use and maintenance of the jet injector device should be followed closely.

Additional information is needed to properly evaluated the risk of transmission from current jet injectors and to develop protocols to ensure the safety of future models. Because infection with hepatitis B, the most infectious bloodborne pathogen and the major transmission risk from injection practices, is usually asymptomatic it is unlikely that transmission of this disease from jet guns would be detected by routine disease surveillance systems in most countries. Asymptomatic hepatitis B infection often leads to chronic viral carriage, cirrhosis and liver cancer. Special studies and laboratory procedures to measure the degree of potential bloodborne disease transmission are needed. Work is underway to develop a new generation of low work load jet injectors with no risk of transmission of blood or bloodborne infections (WHO, 1996).

The CDC/WHO conference led to further discussions about jet injector safety within CDC and WHO, initiated discussions within the FDA, and would later prompt the manufacturer of Ped-O-Jet to withdraw it’s product from the Department of Defense.

These subsequent discussions have been outlined within the following articles:


  • (Chen) Chen, Robert. Curriculum Vitae. Accessed January of 2015.
  • (Fields, 1996) Fields R. Participation in Meeting: Jet injectors for immunization; current practice and safety; improving designs for the future. WHO/CDC Meeting. Atlanta, GA. 2-3 October, 1996. Available at:
  • (PATH, 1996) PATH. Low-workload Jet Injectors For Vaccine Delivery: 1987-1996. Program for Appropriate Technology in Health. 18 September 1996. pp. 1-5.
  • (WHO, 1996) World Health Organization. Safety of Injections in Immunization Programmes. WHO/EPI/LHIS/06.05.
  • (WHO, 1997) World Health Organization. Steering group on the development of jet injection for immunization. May 14, 1997. [draft]

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