Which of the following OPV vials are usable?
(b) Only 1, 2Rules for VVM use in India* Rule 1: If the inner square is lighter than the outer circle, the vaccine may be used (Vials 1, 2)* Rule 2: If the inner square is the same colour as, or darker than, the outer circle, the vaccine must not be used (Vials 3,4).
Only 1
Only 1,2
Only 1,2, 3
Only 3, 4
Environment and Health