Yellow Fever Vaccination with Cultivated Virus and Immune and Hyperimmune Serum

Abstract

Summary 1. Forty-four people were vaccinated against yellow fever in Brazil in 1935–1936 with human immune serum and a strain of virus cultivated in mouse embryo tissue (17E). The method is safe and effective, but can be applied to only small numbers, owing to the limited supply of suitable serum and the cumbersome technique involved. 2. During the same years, 234 persons were vaccinated with the same virus and various pools of immune goat serum. Although satisfactory immunization was secured, this method cannot be recommended because of serum reactions and delayed febrile reactions with circulating virus attributed to the rapid excretion of the heterologous serum. 3. In 1936–1937, a total of 795 persons were vaccinated with hyperimmune monkey serum and the same tissue culture virus. Apparently antibodies in rhesus serum are more effective than those in goat serum. The relatively high percentage of failure to immunize encountered with this method is attributed to the use of excessive amounts of antibody, resulting in a complete inhibition of activity of the virus. 4. A delayed reaction of unknown etiology occurring from two to eight months after vaccination, the main symptom of which is jaundice, was reported in from 20 to 30 per cent of a series of vaccinations done with two pools of hyperimmune monkey serum.