Dec 04, 2017 · An MCV vial is opened as soon as an eligible child comes to the facility: 2 (0, 5) 6 (0, 20) An MCV vial is opened only on certain days or when a certain number of children are present at the facility: 98 (95, 100) 77 (48, 100) I wait for children to gather to a minimum number before opening a MCV vial: 60 (25, 95) NA: General vaccine wastage