[Smallpox vaccine, then and now. From the "cow lymphe" to the cell-culture vaccine].

There have been few changes in the preparation of smallpox vaccine since Eduard Jenner described his method of preventive inoculation in 1798. Jenner's vaccine, "the matter", was maintained in man by arm to arm passage. The only major achievement in production methods was the introduction of an animal host for virus propagation. The skin of living calves or sheep was inoculated with seed virus and the "pulp" harvested three to four days later. The disadvantages of this procedure are evident: massive bacterial contamination in spite of rigorous cleanliness and excessive amounts of undesired tissue debris in the crude material to be used for vaccine production. In spite of these obvious disadvantages the method is still in use all over the world. Advances in tissue culture techniques have led to the production of all modern vaccines for use in animals and in the human from this substrate with low initial content of foreign protein and of primary sterility. The only exception today is conventional smallpox vaccine. Sporadic attempts to produce smallpox vaccine in tissue culture have been recently and successfully made in England, Holland and Yugoslavia. The Bavarian State Institute of Vaccination has adopted Vaccinia strain Elstree to primary cultures of chick embryo fibroblasts. The virus propagation in roller bottles permits the economical production of a high titered vaccine with a stability equal to that of calf origin. The cell culture harvest is bacteriologically steril and has a minimal content of foreign protein. Within the past two years this cell culture vaccine has totally replaced the old "calf lymph". Vaccination takes are equal, complications have so far not come to our attention.