A Vaccine Vial Monitor (VVM) shows the inner square darker than the outer circle. This means the vaccine should be:
- A Used immediately as cold chain has been maintained
- B Kept at room temperature and used within 24 hours
- C Discarded as the vaccine has been exposed to excessive heat ✓
- D Placed in the deep freezer to restore potency
Correct answer: C. Discarded as the vaccine has been exposed to excessive heat
Explanation
A VVM reading where the inner square is darker than the outer circle (Stage 3 or 4) indicates the vaccine has been exposed to excessive heat and its potency may be compromised — the vial must be discarded and not used. If the inner square is lighter than the outer circle (Stage 1 or 2), the vaccine can still be used. Once discarded, cooling cannot restore potency.
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.