Protective Effect of Vaccination Against Induced Influenza B 1

In the previous paper (1), evidence was presented to show that subcutaneous vaccination of human subjects with a vaccine containing in- activated influenza viruses, Types A and B, was followed by an increased resistance to experi- mentally induced infection with influenza virus, Type A. The present report deals with the clini- cal and laboratory results of a similar study illustrating the effect of subcutaneous vaccination upon resistance of another group of individuals to induced infection with influenza virus, Type B. 10-3, 4, 4 10-J 3,4,4 10-4, 4, 5 10-i 5, 6, +++ fected allantoic fluid that was employed for the human infection. The mouse lung tissue consisted of a pool of lungs containing virus which had been passed 1 to 5 times in mice, after 9 to 12 passages in ferrets. Allantoic fluid from the second and third egg transfers was concen- trated approximately 10-fold by adsorption onto red blood cells of the embryo and elution into physiological salt solution (3). Fluid containing the virus was placed in a rubber-capped vaccine vial and stored at 40 C. for one week before use. Tests for sterility were made. At the time the fluid was used to infect humans it had the following properties: