Vaccine Vial Monitor

It is a heat sensitive square within a circle, which changes colour under the combined influence of heat and time.

If after exposure to heat for a certain amount of time, the square reaches the same colour or becomes darker than the circle, the vial should be discarded.

The VVM allows the user to see at any time if vaccine can still be used in spite of possible cold chain interruption. This helps to reduce vaccine wastage.

The use of VVM offers several advantages during national immunization days or mop-up campaigns. Field workers can carry OPV without ice for door-to-door vaccination. The need for large number of froz3en ice packs and re-supply of ice is reduced as one can know when the OPV vial has reached the discard point due to exposure to heat. This helps teams to cover longer distance and spend more time in field as they no longer have to carry bulky equipment or rely on resupply of ice. Because of this, it is also easier to organize immunization in areas that are difficult to reach or have weak cold chain. The need to expand cold chain facilities for the campaigns is greatly reduced. Thus VVM helps to plan a cold chain which is more flexible, less stringent and cheaper.