Thermal instability and infectivity loss on drying are well-recognized properties of measles virus.1-4 Obviously, these difficulties must be overcome in preparing live measles-virus vaccine for general use.
The present brief report summarizes early findings in investigations of stability of liquid, frozen, or dried measles-virus vaccine prepared in our laboratories.
Materials and Methods
Vaccine.—All lots of Enders' live attenuated measles-virus vaccine (Edmonston strain) were prepared in tissue cultures of chick embryo according to Enders et al.4 Dried vaccine contained an added stabilizer. Frozen vaccine was stored at —70 C in a solidified carbon dioxide (Dry Ice) refrigerator in flame-sealed ampoules. Dried vaccine was sealed in vacuo in ampoules with rubber closures. These were capped with aluminum seals and covered with a thermoplastic wax to provide a moisture barrier. Rehydration was carried out with sterile distilled water without preservative. Pools of 3 vials were made for titration purpose.Infectivity