The stability of the viral potency of smallpox vaccine when prepared in the globulin and other protein fractions of calf plasma, dehydrated, and stored at tropical temperatures.

Abstract

Abstract A dehydrated smallpox vaccine prepared with calf globulin is described. The vaccine had sufficient viral potency to warrant its use for human vaccination after exposures of 90 days to 37.5 °C. and 60 days to 45 °C. Dehydrated smallpox vaccines prepared with the euglobulin, pseudoglobulin, and albumin fractions of plasma demonstrated relatively low resistance to high temperatures. A dehydrated smallpox vaccine prepared with the fibrin fraction of calf plasma demonstrated good resistance to high temperatures. Data submitted suggest that the element contained in calf globulin that has protective qualities for dehydrated smallpox virus when it is exposed to high temperatures is thermolabile. Simultaneously with the preparation of the vaccines, the bacterial count of each was diminished to an acceptable figure in spite of the use of highly contaminated calf pulp as the virus source.