A Vaccine Vial Monitor (VVM) on an OPV vial shows the inner square colour that is DARKER than the outer circle. The correct action is:
- A Use the vaccine immediately as it is still safe
- B Discard the vial as the cold chain has been compromised beyond the discard point ✓
- C Refrigerate the vial for 24 hours before use
- D Send the vial to the district cold chain officer for evaluation
Correct answer: B. Discard the vial as the cold chain has been compromised beyond the discard point
Explanation
VVM stages 3 and 4 indicate heat damage. In stage 3, the square colour matches the circle; in stage 4 (the discard point and beyond), the inner square is darker than the outer circle — indicating that cumulative heat exposure exceeds the threshold. Vaccines in stages 3/4 must be discarded. At stages 1 and 2, use is appropriate (square lighter than circle).
Reference: Park's Textbook of Preventive and Social Medicine, 27th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.