POST 00444E : IMPACT OF VACCINE VIAL MONITORS (VVM) ON THE USE and DELIVERY OF MEASLES VACCINE

POST 00444E : IMPACT OF VACCINE VIAL MONITORS (VVM) ON THE USE and DELIVERY OF MEASLES VACCINE Follow-up on Posts 00433E and 00441E 3 April 2002 ______________________________________________________________________________ �mit Kartoglu further contributes on the topic of VVM use for measles vaccine. ______________________________________________________________________________ I am very pleased to see the interest in the use of VVMs on all vaccines. I am currently in Vietnam to assist in the evaluation of the study and to conduct qualitative assessments with groups involved in the measles campaign (study and control groups). I hope to release the results soon after clearance by national authorities. Behavior of measles VVM There are four types of VVMs as described in the latest specifications (E6/IN5 dated 25 March 2002). Their reaction times vary depending on the category. VVMs are assigned by WHO based on the stability data provided by the vaccine manufacturers. All VVMs for OPV are VVM2 type meaning that if kept at 37oC, they reach their discard point in 24 hours (2 days). VVM for measles used in Vietnam measles campaign were from Chiron Italy and VVM7 type were attached (7 days to end point at 37oC). This means VVMs on different vaccines will behave differently. However, as indicated in Femi's message, VVM change color faster at higher temperatures, because this is the whole purpose of it, VVM is like a data logger attached to a vial recording the heat exposure. As for the "stretching" the chain as we use to do for OPV with VVMs (fast chain), we have to consider the differences in presentations. Measles as all other freeze-dried vaccines need ICE following reconstitution to be kept on. In this regard, use of measles vaccine with VVMs in areas with no cold chain or very weak cold chain becomes quite tricky and requires very good level of supervision. VVM reaction rates by category of heat stability is shown in the following table (reproduced from the "Specifications for Vaccine Vial Monitor - E6/IN5, 25 March 2002): ---------------------------------------------------------------- VVM type 37oC 25oC 5oC ---------------------------------------------------------------- VVM30 30days 193days >4years VVM14 14days 90days >3years VVM7 7days 45days >2years VVM2 2days NA 225 days ---------------------------------------------------------------- ##text##