A PHC medical officer wants to give pulse polio immunization. The following finding in the Vaccine Vial Monitor (VVM) indicates that the vaccine should not be used:
c. Inner square matches the color of the outer circle(Ref: Nelson's 20/e p 1561, Ghai 8/e p 190-194)Interpretation of the color change of VVM is as follows:Inner square is white, or lighter than outer circle: If the expiry date has not passed, vaccine can be usedInner square matches color of outer circle or is darker than outer circle: Vaccine should be discarded, regardless of the expiry date.