The Vaccine Vial Monitor (VVM) on an oral polio vaccine vial shows that the inner square is darker than the outer circle. What should the health worker do?

• A Do NOT use the vaccine — the VVM indicates heat damage beyond usable threshold ✓
• B Use the vaccine if it has not expired
• C Warm the vaccine to room temperature and re-read the VVM before use
• D Report to the cold chain officer but still administer if less than 4 hours since removal from cold chain

Explanation

The VVM uses a colour-change indicator that progressively darkens with cumulative heat exposure. If the inner square is the same shade as or darker than the outer reference circle, the vaccine has been exposed to excessive heat and should NOT be used, regardless of expiry date. This is called the 'discard point.' The VVM has four stages: Stage 1 (usable), Stage 2 (use with caution, approaching discard), Stage 3 (discard point), Stage 4 (discard). When the inner square matches or exceeds the outer ring, the vaccine must be discarded.

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.