Since December 1974, when revised regulations concerning shipment of live virus vaccines issued by the Food and Drug Administration, Bureau of Biologics, went into effect, Merck Sharp & Dohme has transported all shipments of our vaccines and diluent syringes in containers with dry ice.
Previously, our live virus vaccines turned pink to red when reconstituted. This color is due to the addition of phenol red, which is a pH-sensitive indicator. Now, however, a few of