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Ce forum est un lieu d'échange où les membres peuvent poser des questions, partager leurs expériences, coordonner des activités, et discuter les récentes avancées en matière de vaccination.
  1. Moderator
  2. la chaîne d'approvisionnement et de la logistique
  3. lundi 16 juin 2008
POST 01281E: DARK SPECKS IN THE ACTIVE AREA OF THE VVM 16 JUNE 2008 ******************************************* Umit Kartoglu of WHO responds to Bal Ram Bhui’s question regarding how to interpret specks in the VVM’s active surface. ----------- Hi everyone, I would like to bring up a color change of VVM which is not exactly as portrayed in VVM education material. Please have a look at a picture file attached herewith. I have seen this kind of VVM in the field often. The inside square is still whiter than the outer circle but started developing black spots inside. This stage is not explicitly mentioned in VVM literature. I would be very much grateful to any opinions, other experiences. I am not sure whether this is stage two or three or four. Thanks Bal Ram Bhui ([email=balram_bhui@YAHOO.COM]balram_bhui@YAHOO.COM[/email]) Indonesia Dear moderator, The information provided by Bal Ram Bhui appears to be a diagram of a VVM showing dark specks in the active area of the VVM. This phenomenon is similar to samples Temptime received back in 2006 from Indonesia. The investigation done on the 2006 samples showed that specks were due to the formulation of the VVM30 ink at that time (manufactured in 2003). The active ink contained a small amount of one monomer component that changes color more quickly than the primary monomer component. Larger particles of this monomer then appear as darker specks in the printed ink over time. The VVM30 is currently formulated so that it no longer contains this component, however, VVM2 (which is used only with OPV) is still manufactured with this component. Without knowing the type of the vaccine, lot number and the manufacturer and therefore the lot number of the VVM and type, we can only assume the cause is similar to our conclusion for the 2006 case. Regardless of the formulation, the darker specks do not affect the performance or visible endpoint determination of the VVM. The specks should be disregarded and the characteristic blue-grey color of the active area (the square) should be used to determine the likeliness of cumulative heat exposure over time and to decide whether vaccine could be used. I would like to thank Ted Prusik, Steve Feldman and Alissa Klopper from Temptime Corp., for their assistance in responding. Cheers, UMIT ([][/email]) Dr. Umit Kartoglu, MD, DPH 
 World Health Organization 
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