POST 00858E : COMBINATION VACCINES, LYOPHILIZED VACCINES, DILUENTS AND VVMS

POST 00858E : COMBINATION VACCINES, LYOPHILIZED VACCINES, DILUENTS AND VVMS Follow-up on Posts 00847E, 00852E and 00855E 18 November 2005 _____________________________________ This posting contains three further contributions to this debate. The first is from Rebecca Fields (mailto:[email protected]) and the second from Andy Tucker (mailto:[email protected]) both from the United States. The third is from Emma Uramis (mailto:[email protected]) from Cuba. _____________________________________ Dear Michel, Very interesting question that you posed on Technet Forum recently. Clearly, the cost benefits of this proposal are extremely attractive. So far, I've seen conflicting opinions from Garry Presthus and Bob Davis. You described a number of possible risky situations. One way to think about the problem is in terms of two intersecting scales: one for likelihood of the risk (i.e. of that risky situation occurring), and the other for the severity of the consequences. If you plot the situations that you described, they come out as follows: 1. Hib used with other diluent: severe consequences, relatively high likelihood given lack of bundling. 2. Reconstituted product goes into DTP-HepB vial: severe consequences, relatively low likelihood. 3. Health workers keep other lyophilized vaccines longer: severe consequence, low to moderate likelihood. 4. Health workers ignore VVM, discard everything after 6 hours: consequence isn't severe, likelihood is pretty low. Two major concerns that affect these assumptions: First, Hib and DTP-HepB aren't physically bundled. We've just heard from one field staff that they're seeing more vials of Hib in the fridges than DTP-HepB, raising questions of whether DTP-HepB is just being given by itself without Hib for some reason. Second, while training might be able to address this issue, we know it often doesn't reach all who are actually carrying out the job and that turnover is a big issue. So there would have to be very clear directions in job aids or posters that stay at the facility. Given the possible risks, these would have to be self-explanatory even to low literacy groups and would have to be disseminated very conscientiously. You mentioned the issue of vaccine labelling. Would vaccine manufacturers be willing to support the proposed practice or would they feel it increases their liability? Best regards, Rebecca Rebecca Fields, Technical Officer, IMMUNIZATIONbasics ------------------------------ Michel I used to work for PATH in Cambodia where I was the primary advisor to the NIP on the introduction of DTP-HepB vaccine. Many of the logisitc and practical issues of poorly-trained/low-capacity health workers in the field are true. The one issue you didn't seem to raise is that the VVM on the Hib vial may not be pertinent to the DTP(-HepB) diluent which may have been kept separate and may be much further along toward "expiration." I don't see a good solution for this unless the diluents can be assured to be kept with the Hib vials and the Hib VVMs are "shorter term" than the diluents, i.e., one can be assured that the diluent won't "expire" before the Hib component. Sounds diifficult. Best wishes, AwT Andy Tucker, MPH Epidemiologist-at-large Earth More specifically: Austin, TX USA ------------------------------ Hello Michel, Regarding the considered risk that "health workers do get confused by the new message and keep other lyophilised vaccines beyond 6 hours after reconstitution", I agree that probability of occurrence may be low however severity of effect could be very serious and in addition there is no possibility of detection. Thus I think this risk is not acceptable because failure may compromise children's safety then I recommend the proposed practice should not be implemented. Concerning your question on what text would be on the label of the Hib vial, I would like to draw your attention to WHO/GMP text for final product identification (TRS 908, Annex 4, item 15.11), which requires in addition to the name of the product, at least the following information : - a list of the active ingredients - the batch number - the expiry date - and any special storage conditions or handling So... how could be handled a recall from a specific batch of Hib vaccine, if the vial is labelled as DPT-HepB-Hib? Hope this can be helpful. 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