Vaccine Vial Monitor

This is a very brief presentation discussing about the VVMs used over the various vaccine vials.

1. VACCINE VIAL MONITOR ROLL NUMBERS: 85-91 1

2. WHAT IS VVM ? A Vaccine Vial Monitor (VVM) is a thermochromic label placed on vaccine vials which registers the cumulative effect of heat exposure over time. VVMs serve primarily to warn health workers when the heat exposure of the vial has exceeded a pre-set limit, beyond which the vaccine should not be used. Moreover, it also guides the health worker to first use more exposed vials. 2

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4. HISTORY In 1979, WHO conceived the concept to create a new technology for monitoring heat exposure to each vaccine vial. PATH(Program for Appropriate Technology in Health) responded to this idea and along with Ray Baughman (of Allied Chemicals Corp.) initiated work to prepare a prototype. Eventually, by the year 1996 after various research and trials, VVMs were finally introduced on all OPVs supplied by the UNICEF. 4

5. POLYMERS Initially, para-toluene sulfonate (PTS) was used in the VVM . DRAWBACKS OF PTS: Reaction rate too slow (for use with OPV). Skin irritation. Printing difficulties . Recently, Diacetylene polymer has been used. Yet, the exact composition has been a guarded trade secret. 5

6. VVM: FORMAT & DIMENSIONS The VVM is a circle of colour, minimum diameter 7.0mm with a square of colour, minimum dimensions of 2.0 x 2.0mm positioned in the centre of the circle. The ratio of the area of the square to the area of the circle(including the square) is to be at least 0.1:1. 6

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8. VVM CATEGORIES 8

9. CONCEPT OF HEATmarker /VVM The inner square of the VVM contains the heat sensitive material that is light at starting and darkens with exposure to heat. This transition is a continuous process. POINT OF FOCUS: START POINT: The colour of inner square is lighter than the circle by at least 0.25 OD when measured by a densitometer. It means the vaccine can be used. END POINT: The colour of the inner square matches the circle ( OD square = 0.00). The vaccine is to be discarded. 9

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12. VACCINES USING VVM OPV: VVMs added to OPV by 1996. Vaccine stored at 2-8 degree Celsius and this is maintained by the “COLD CHAIN” CONTINUOUS AMBIENT TEMPERATURE (DEGREE CELSIUS) NUMBER OF DAYS BEFORE OPV WILL REACH END POINT +37 1.5 – 2 days +25 7 days +4 6 months -20 2 years 12

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14. HEPATITIS B: The use of vaccine vial monitors has helped health workers remain confident in vaccines being stored outside the cold chain. 14

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16. Thank You 16