The Vaccine Vial Monitor (VVM) on a DPT vial shows the inner square matching the outer circle in color. At which VVM stage is this vial?
- A Stage 1
- B Stage 2 ✓
- C Stage 3
- D Stage 4
Correct answer: B. Stage 2
Explanation
Stage 2 of VVM is when the inner square matches the outer circle in color. At this point, the vaccine can still be used. Stage 3 (inner square darker than outer) and Stage 4 (inner square much darker) indicate discard. Stage 1 is inner square lighter than outer, indicating safe use.
Reference: Park's Textbook of Preventive and Social Medicine, 26th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.