Unsterile Mass Jet Injections: CDC Researchers Divulge Hazards of Ped-O-Jet Injectors During 1960s & 1970s Mass Vaccination Campaigns

During the 1960s and 1970s, the Communicable Disease Center (CDC) sent young men to traverse the globe in a noble effort to control outbreaks and eradicate viruses. Two of the most notable mass vaccination campaigns were the Smallpox Eradication Program and the Measles Control Program. Recently, the CDC has made accessible the interviews of these admirable men reflecting upon their travels. These interviews reveal the true first-hand accounts of how mass vaccination campaigns were conducted abroad and includes information previously not included within scientific studies. Their honesty has been greatly appreciated.

“We didn’t really use much sterile technique.”

Researchers recall the lack of sterilization within their interviews.

“The jet injector nozzle actually did press up against the skin,” said Dr. William Foege in a 2006 interview at CDC Headquarters in Atlanta, Georgia. “At that time, people were quite sure that there was no chance of cross-contamination, that the vaccine came out at high pressure, but we’ve subsequently changed our mind about this, and that’s why we don’t use jet injectors at this point” (Harden, 2006a).

Dr. Foege, the former Director of CDC from 1977-83, served in the Smallpox Eradication Program in Nigeria in his early years as a missionary and then as a CDC staffer. During his career he administered tens-of-thousands of jet injections and he now acknowledges that the previous understanding of jet injector safety was incorrect and jet injectors due, in fact, pose a risk of cross-contamination.

Another CDC researcher, Dr. Deane Hutchins, served in CDC’s Smallpox Eradication Program in Nigeria and Sierra Leone. Dr. Hutchins also described lack of sterilization.

I realized that you could train uneducated people to do a health program. For example, these vaccinators that we had had very little education. Sterile technique was still unheard of, and we didn’t really use much sterile technique. We did not clean off arms before people were vaccinated. We told the vaccinators that if they dropped the nozzle of the jet injector on the ground, clean it off with some alcohol or something. They would just brush it off and put it back on. We did studies to see if there were any adverse effects, and there was no significant increase in infections from this lack of sterile technique (Harrar, 2006).

Yet the tests to ascertain any adverse effects from the use of the Ped-O-Jets were not capable of testing for Hepatitis B, Hepatitis C or HIV at the time. In fact, these viruses were still unknown to mankind.

Dr. Stanley Foster, who served in CDC’s Smallpox Eradication Program in Nigeria and Bangladesh, stated in a personal interview with this author, “At that time the question was the effectiveness of the Ped-o-Jet not the risk of infection” (Foster, 2017).

CDC photographs have also captured the lack of sterilization during these vaccination campaigns. The following photograph captures a young child receiving a smallpox vaccination in Nigeria in 1969. Notice the mass vaccination is being conducted within a field and the vaccinator is bare foot. When the jet gun is stowed in the carrying case it rests next to the foot pedal. Therefore, any dirt on the pedal would fall and contaminate the jet gun. Also notice the second vaccinator, who is wearing a hat, is smoking a cigarette while he awaits to give a vaccination.

1969 Smallpox Vaccination in Nigeria - Lack of Sterilization

(Unknown, 1969)

This photograph, captured during a mass vaccination in Nigeria, documented bleeding at the injection site. Notice the young girl in the center of the photo, standing to the right of the vaccinator dressed in a white lab coat. The girl is holding her right bicep after receiving a Ped-O-Jet injection. Now notice the infant being held on the far right side of the image. Upon his bicep is a piece of cotton or cloth tinged with a droplet of blood.

Nigerian parents brought their children for smallpox vaccination

Locals Trained to Be Vaccinators

Local healthcare workers were trained in the use of the Ped-O-Jet, as shown in this 1968 photo of Nigerian healthcare workers after a training class. Dr. Hutchins had noted at certain times “uneducated” locals were trained to administer vaccinations (Harrar, 2006).

1968 Ped-O-Jet Training Class in Nigeria

(Unknown, 1968)

Speedy Injections

Dr. Foege described the haste at which the immunizations were given.

You set up a rhythm: grab the arm, step on the hydraulic lever, shoot, and the person would continue on. You could do a thousand people an hour, and I remember at one point doing a prison in eastern Nigeria, where they had the inmates lined up, and they were actually pushing them through by hitting them with sticks. I did 600 people in twenty minutes, because it was such a regimented line that you could just grab people and do them so fast. At one point, I recall doing over 11,000 smallpox immunizations in one day. So, yes, you could do this very quickly (Harden, 2006a).

Bob Baldwin, who served as CDC’s Regional Operations Officer in French-speaking West Africa, remembers the chaotic crowds.

I do remember being out there and immunizing kids with a ped-o-jet in each hand, smallpox in this gun and measles vaccine in this gun, and I’m pushing down on the foot pedal for this gun, to charge it and give the kid an immunization, and the other one with the other hand. And they’re crowding around, and crowding to the point where you couldn’t work. The Africans were so afraid that you were going to run out of vaccine, that their children weren’t going to get immunized, that they would just…And so I had to, a number of times I had to stop and just say to the headman or to the chief, you’ve got to get the people lined up, in a line. I can’t work here. I mean, if I can’t work, I can’t immunize them (Diallo, 2006).

Unbeknownst to Mr. Baldwin holding a jet injector in each hand was an improper technique. The vaccinator must hold the jet gun in one hand and use his or her opposite hand to support the vaccinee’s arm as well as to pull the flesh tight to receive a proper vaccination.

Frequent Maintenance Repairs

Despite the effectiveness and efficiency of the Ped-O-Jets, the guns required frequent maintenance and repairs.

Dennis Olsen, who served as an Operations Officer for CDC’s Smallpox Eradication Program in Liberia, recalled the vast amount of training that went into learning how to repair the Ped-O-Jet injectors.

I spent a lot of time in training programs because we were using Ped-O-Jet equipment, and so we spent a lot of classroom time in operations maintenance of it. And, of course, we had to wait for supplies to come in (Drew, 2006a).

David Bourne, who assisted in CDC’s mass vaccination campaign in Ethiopia while serving as a Peace Corps volunteer said the jet guns “often broke down especially in the desert” (Decker, 2008).

Another researcher described the poor-quality with which the Ped-O-Jet was made. “Unfortunately, the Ped-O-Jets were not made for the military. They were made for CDC by a firm in New York, and I don’t think they were up to the same quality level,” said Jay Friedman, who served as CDC’s Operations Officer in the West African nations of Mali, Gabon, and Nigeria (Drew, 2006b).

However, Mr. Friedman is misinformed. The Scientific Equipment Manufacturing Corporation (SEMCO) manufactured both the electric model known as the Multidose, and the non-electric foot pedal known as the Ped-O-Jet. When SEMCO sold-off the devices to Vernitron Medical Products, both devices were still manufactured under one company. Moreover, the U.S. military not only invented but also used both the electric and foot-operated models. Therefore his assumption that the jet injectors were not being made to the same quality is inaccurate. His personal testimony about the functioning of the Ped-O-Jet injectors and the quality of their parts, however, carries valuable weight and insight.

Mr. Friedman continued to say,

The guns would break-not so much break, as their internal valves and springs would wear out or get stuck. The nozzles would clog, for which we had special wires to ream them out. And especially the pedal, the pedal pump. I think they were made of aluminum with Teflon O-rings acting as piston rings. And this aluminum, being a soft metal, would wear out very quickly. Being an ex-mechanic, I had to fix them all the time, although I trained Malians to work on them, which is not very difficult. And we spent a lot of time fixing these Ped-O-Jets. In fact, in Mali, we had 1 guy, a vaccinator, assigned full-time to work on Ped-O-Jets that were being used out in the field. So we had to transport them back to the capital to have this guy work on them. The simple repairs could be done in the field. But any time the pedal pump broke, you had to send it in. You had to re-machine the whole piston when that happened… (Drew, 2006b).

The following CDC photograph shows Operations Officer, Lloyd Wade, repairing a Ped-O-Jet in 1967 while smoking a cigarette.

1967 Ped-O-Jet Repair While Smoking Cigarette

(Robbins, 1967)

“Lack of good communication…”

Bob Baldwin also recalled how the Ped-O-Jets would breakdown and the urgency of acquiring the parts to fix the guns for the next campaign.

…the lack of good communications in those days. I mean, back and forth to where you needed, either to alert people that you were coming to a certain village on a certain day to immunize, or it was communicating to Lagos, to the site we needed certain ped-o-jet parts, because, you know, 10 of our guns are down, and we really need these for the next campaign, and the rainy season is coming, and we need them tout suite, you know, right away (Diallo, 2006).

Dr. Ralph Henderson, who served as CDC’s Deputy Director of the West African Smallpox Program and later served as an Assistant Director General for the World Health Organization’s Expanded Immunization Program, described the troubles of getting Ped-O-Jet parts and the lack of supplies.

One of my problems as advisor was firing off cables about getting spare parts for the jet injectors. They kept running out of some tiny points-I didn’t know what they were, but I think that on a regular engine they’d be called the points. They relate to the electrical system. Forget it. But that’s all I knew. And I knew that they were burning out, and they couldn’t get spare parts. So one of my jobs as a technical advisor, very technical, was to send cables back saying, “Send more of these things because they can’t run the injectors.” Nor did CDC send enough diluent, so we were often using Evian, one of the French bottled waters, as diluent for the measles vaccine (Harden, 2006b).


These interviews give us several insights. For instance, we gain: 1) knowledge of what the CDC thought of jet injectors during the 1960s; 2) knowledge of how jet injectors were administered, and 3) knowledge about the performance of Ped-O-Jet injectors.

During the 1960s the CDC assumed the high velocity of the jet stream would not allow any cross-contamination. A common idea of the time that since there was no needle there was no risk. Although no safety test was conducted to confirm this assumption. As Dr. Foster stated, “At that time the question was the effectiveness of the Ped-o-Jet not the risk of infection.” However, as Jet Infectors has previously reported, the CDC first evaluated the safety of jet injectors in 1977 and found cross-contamination was possible.

The CDC researchers interviewed now admit there was no sterile technique when using the Ped-O-Jet. Bill Foege, the former Director of the CDC, acknowledged the Ped-O-Jet allowed for cross-contamination. Other interviews revealed vaccinators failed to sterilize the nozzle after accidentally dropping the Ped-O-Jet on the ground. Photographs captured vaccinators smoked cigarettes when performing inoculations and maintenance on the jet gun.

In numerous interviews are evidence that vaccinators used the Ped-O-Jet improperly. In one instance, a vaccinator held a jet gun in each hand, which means he failed to support the arm of the vaccinee and thus the injection was administered incorrectly. Several interviews reported vaccinators administered thousands of injections within a short time. Administering 600 jet injections in twenty minutes would mean an injection was given every two seconds (one second for the vaccination and another second for the next person in line to step-up). This demonstrates the vaccinator failed to hold the jet gun against patients’ arms for a full three seconds as per the manufacturer’s recommendation. In one instance, vaccinators used Evian water in the absence of diluent, yet the effectiveness of such an on-the-fly concoction was never previously tested.

The interviews also document numerous maintenance issues. Mr. Friedman noted the shoddy quality with which the Ped-O-Jets were made. The nozzle often became clogged and required being “reamed” out with a wire brush, thus potentially damaging the nozzle orifice. Moreover, the wearing of O-rings and the destruction of the aluminum foot-pedal demonstrate these Ped-O-Jet injectors were used beyond their intended life span.

Whether used within mass vaccination campaigns or within the United States military, Ped-O-Jets were assumed safe, administered by vaccinators with limited training, conducted in haste, at times improperly used, and faced frequent maintenance issues.

In no way is this article to assign blame to any of the CDC researchers interviewed, to the CDC in general or to the local volunteers who partook within the vaccination campaigns. At the time, knowledge of blood-borne pathogens was primitive. This article is purely to document how the Ped-O-Jet injectors were used and to gain a better understanding of what the CDC knew and thought of jet injectors throughout the 1960s and 1970s.


© Jet Infectors, 2016 – 2021
Fair Use Notice (17 U.S.C. § 107)

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