Influenza virus strains A2/Port Chalmers/1/73 (H3N2) and B/Hong Kong/5/72 were adapted to mice by serial passage of virus infected mouse lungs. The adapted viruses were used to challenge mice after they had been immunized with serial dilutions of several bivalent vaccines, containingboth A/Port ChalmersandB/Hong Kong antigens. Vaccines included both whole virus and split-product preparations di...
