Brazilian Government Notes Risk of Ped-O-Jet Injectors: Prompts Investigations by CDC and WHO in the Early 1990s

The Brazilian Ministry of Health implemented safety testing upon Ped-O-Jet injectors in the late 1980s and early 1990s. The investigation was intended to uphold the safety of jet injectors but rather discovered the most widely-used device, the Ped-O-Jet, was a safety risk.

In 1987, a Measles Control Program was initiated within the São Paulo region of Brazil. A total of 8.7 million children aged nine-months to fourteen years were vaccinated with Ped-O-Jet injectors. Despite a hepatitis outbreak at a Los Angeles clinic with a Med-E-Jet injector, the healthcare workers in São Paulo believed the Ped-O-Jet was different and posed no risk (de Souza Brito, 1996).

The Brazilian Ministry of Health conducted a study to assure the safety of the Ped-O-Jet during routine military vaccinations in 1991 (de Souza Brito, 1996). The study aimed to answer three questions:

  1. What is the frequency of visible bleeding at the site of jet injection in the skin?
  2. What is the frequency of occult blood in the next vaccine shot dose?
  3. Is there any correlation between visible bleeding and occult blood of the next dose?

Glacus de Souza Brito and his fellow researchers led the investigation. It was observed amongst three vaccination sites the percent of vaccinees who bled immediately after the Ped-O-Jet was removed ranged from 2.2 to 23.3 percent. The average percent of bleeders was 3.6 percent (104 out of 2885). The researchers found “instantaneous bleeding took place after injection in a significant proportion of cases and that there was therefore a risk of downstream infection of subsequent subjects” (WHO, 1998).

The presence of blood prompted researchers to asses the possibility of cross-contamination. The subsequent shot after administering a vaccination was fired into a vial and analyzed. Amongst the three vaccination sites results detected blood within 0.2 to 6.6 percent of the ejectates, with the average being one percent (28 cases out of 2885 vaccinees).

The researchers found, “there was little to no correlation between visible bleeding and detection of occult blood in the successive vaccine doses. Only one person had both” (de Souza Brito et al., 1994; de Souza Brito, 1996). This finding is significant. There was no visible bleeding at the injection site in 27 out of 28 of the ejectates which contained blood, indicating blood transferred within microscopic levels not visible to the human eye.

Dr. Martin Friede of the WHO later noted, the researchers used blood detection stripes which can only detect around 2,000 picoliters of blood and therefore failed to detect blood within levels lower than 2,000 picoliters. The results demonstrated one percent of the ejectates contained 2,000 picoliters of blood (FDA, 2005). Therefore, the results found blood was being cross-contaminated via the Ped-O-Jet within volumes which could contain infectious viruses like Hepatitis B and Hepatitis C.

In 1992 a mass Measles Vaccination Campaign was launched across the entire country of Brazil. The government purchased 10,000 Ped-O-Jet injectors to vaccinate an estimated 50 million children between the ages of nine-months to fourteen years within a month period. During this mass vaccination campaign, a possible hepatitis B outbreak by Ped-O-Jet injectors was investigated but no statistical association was found. However, despite these findings the Brazilian government found the Ped-O-Jets were unsafe and stopped using the devices (Fields, 1996; de souza Brito, 1996).

These investigations by de Souza Brito were significant in raising safety concerns of jet injectors amongst the WHO and CDC. By 1994, Dr. de Souza Brito collaborated with researchers at the CDC to further investigate the inherent risks of Ped-O-Jet injectors. CDC Retests the Safety of Jet Injectors in 1993-94


  • (de Souza Brito, 1996) de Souza Brito G. Multi dose jet injectors and safety aspects in Brazil. CDC & WHO Meeting on Jet Injectors. Atlanta, October 2-3, 1996. (communication paper).
  • (de Souza Brito et al., 1994) de Souza Brito G, Chen RT, Stefano IC, Campos AM, Oselka G. The risk of transmission of HIV and other blood-born diseases via jet injectors during immunization mass campaigns in Brazil. 10th International Conference on AIDS, Yokohama, 7-12 August 1994;10(1):301 (abstract no. PC0132,
  • (FDA, 2005) FDA. General Hospital and Personal Use Devices Panel of the Medical Devices Advisory Committee. August 9, 2005. 35th Conference. Washington, D.C.
  • (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:
  • (WHO, 1998) World Health Organization. Technet Consultation. Expanded Programme on Immunization. Conference 16-20 March 1998. Copenhagen. WHO/EPI/LHIS/98.05.

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