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  3. Tuesday, 22 January 2002
POST 00417E : NEEDLE-FREE INJECTOR FOR MASS IMMUNIZATION CAMPAIGN Follow-up on Posts 00405E, 00408E and 00411E 22 January 2002 _____________________________________________________________________ Hans Everts of WHO, tells us that some ten years ago he has worked extensively with now outlawed models of jet injectors in the field. The ethical question raised by Michel certainly requires attention. The difference between risk inherent to the appliance or related to its use is relevant, but can not be the basis for an absolute rejection in the first case. Polio vaccine causes polio 1 case on every few million doses give, and yet it is considered an acceptable vaccine. The operational points raised by Mary are important. When he worked with jet injectors in the field, one of the main problems was how to deal with mechanical problems during an immunization session 1) to bring a spare jet injector usually does not work, because it will be used from the beginning to speed up the session (remember that everybody can use them with a very minimum of training) 2) to repair in the field is possible, but I have never seen a decent sterilisation afterwards. The move from sterilisable to AD syringes will make that even harder. Sterilisation with chemicals is not an option. Flushing with a full vial of diluent, as was at the time recommended, is not effective and is not done anyway Hans thinks the recommendation should be that if the injector breaks down, the team switches to AD syringes. The injector is then repaired back in the health centre, where there is not an impatient crowd waiting and wondering why it takes so long to sterilise. Introducing jet injectors can only be done safely if technicians are trained correctly and if the injectors are withdrawn from the field after the campaign for maintenance and to prevent they are used for routine EPI. Years ago he has seen some countries using jet injectors in routine programmes. There are a number of reasons why he would strongly recommend against that 1) you would basically need an injector per antigen, which makes economically no sense. 2) the speed gain in campaigns is not a priority for routine and is anyway largely lost during routine sessions where recording is the most time-consuming part and not the actual injection. 3) not all antigens can be given with the injector. 4) sterilisation of the injector in an AD environment will not work. 5) maintenance requires skills and spareparts, both of which need continuous attention. Hans is very much in favour of jet injectors. He thinks we simply can not do without them given the increased number of campaigns, but their introduction and use require careful planning and excellent supervision. He can still see this health worker trying to make the nozzle of his injector air tight with a set of pliers, because he never received the correct gasket. Michel Zaffran < [log in to unmask] > says that he understands well the statement and detailed explanations given by Bruce Weniger on the 510 k license. It is thus critical that the injector we are discussing be submitted to a FDA "premarket approval"- which is not the case yet. In reply to Darin's statements, Michel would remark that 1) he would be delighted to see the advent of a safe multidose jet injector and he does hope that this device will be shown to be risk free! 2) the Sicim (Italy) jet injector which also had a disposable cap was shown to nevertheless carry a substantial risk of cross contamination. 3) the speed issue was shown to not be a true one. Studies carried out in Paraguay by PAHO and WHO in the 1990's in mass measles campaigns, demonstrated that well trained health workers can immunize as many children with syringes and needles as with jet injectors. Since it is most unlikely that jet injectors of this type will ever be affordable and practical for use in routine immunization sessions, if we agree that the speed factor is not a real advantage, then the main (important) reasons to pursue the development of a safe multi-dose jet injectors would be i) reduced cost per injection and ii) reduced amount of contaminated sharps/waste. iii) demonstrated absence of risk of cross contamination because the use of an inherently dangerous device cannot be ethically justified. ___________________________________________________----------------------------------------------------------------------------- All members of the TechNet21 e-Forum are invited to send comments on any posting or to use the forum to raise a new discussion or request technical information in relation to immunization services. Starting in January 2002, TechNet21 e-Forum will have 3 language versions: English, French and Spanish. 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