August 03, 2001

By N.R. Saltmarsh, staff medical writer – Jet injectors may be ideal for mass immunization programs but not until design refinements eliminate their capacity to transmit blood-borne infections, say researchers working in England.

The injectors, which are needleless systems that penetrate skin with high-pressure fluid, have potential advantages over needles and syringes, but P.N. Hoffman and associates at the Laboratory of Hospital Infection, London, sought to determine whether they might have a major disadvantage as well.

They used a highly sensitive enzyme-linked immunosorbent assay (ELISA) to detect whether small amounts of blood and fluid remained in the jet injector after injecting inert buffer into calves.

All four injectors tested – two with reusable heads and direct skin contact, one with single-use injector heads, and one with an injector head that discharged at a distance from the skin – contained at least 10 pl of blood, enough to transmit hepatitis B infection, reported Hoffman and coworkers ("A model to assess the infection potential of jet injectors used in mass immunization," Vaccine, July 2001;19(28-29):4020-4027).

"The source of the contamination was consistent with contamination by efflux of injection fluid and blood from the pressurized pocket in tissue that is formed during injection," reported Hoffman and coauthors. "This insight should inform the design of safe jet injectors."

For more information about this study contact P.N. Hoffman, Laboratory of Hospital Infection, Central Public Health Laboratory, 61 Colindale Ave., London NW9 5HT, UK.

Key points reported in this study include: * Needleless jet injector systems are potentially beneficial for mass immunization programs, but they may transfer blood-borne viruses * Researchers used a highly sensitive ELISA to evaluate whether small volumes of blood remained in the jet injectors after injecting calves with a buffer solution * All four injector models tested transmitted more than 10 pl of blood, the minimum amount required for Hepatitis B transmission, and the quality of the blood was consistent with efflux from the pressurized pocket created by the jet injector.

The editors of Vaccine Weekly, from staff and other reports, prepared this article.

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FDA Home Page | CDRH Home Page | Search | CDRH A-Z Index | Contact CDRH General Hospital and Personal Use Devices Panel Meeting - August 9, 2005   Charles E. Edmiston, Jr., Ph.D., Chairperson, presiding.   During the panel meeting this question posed by Dr. Edmiston to MARTIN FRIEDE, Ph.D., Initiative for Vaccine  Research, World Health Organization: CHAIRMAN EDMISTON: If the devices are used in a compliant manner the way they're meant to be used, do you think the devices are safe? DR. FRIEDE: The devices that we have seen without a protection cap, we have data from the calves and the data from the Hoffman study in Brazil to show that frequent contamination of the ejected did take place. And that contamination was clearly of a level of blood that we are convinced can carry disease. So the devices which do not have a protection cap which are to be used for giving intramuscular injection we are convinced that these carry a significant risk. Minutes from Panel Meeting MORE: DR. FRIEDE:2001, this has already been mentioned, a meta analysis of hepatitis  B in Brazil showed that people who had received the yellow fever vaccine via a  jet injector were much more likely to have also been infected by hepatitis B.  Yellow Fever vaccine via a jet injector For more information on Military risk factors visit HCVets.com