The efficiency of cold chain system for oral polio vaccine as monitored by Vaccine Vial Monitor (VVM) depends on:: (A) Change in the colour of vaccine, (B) Temperature indicator of the system, (C) Viral potency test, (D) Change in colour of monitor
Answer is D. Vaccine Vial Monitor (VVM) - Heat sensitive label that indicates cumulative heat exposure over time. - Whether the OPV l can be used or not depends upon the irreversible colour changes in vaccine l monitor. - If color of inside square lighter than outside circle - We can use the vaccine