Potency of influenza vaccines: mouse protection experiments in correlation to field studies in man

The seroconversion rates have been studied following vaccination of human volunteers with two commercial influenza vaccines. Vaccine A did not give a significant increase of hemagglutination-inhibition titers. Vaccine B, on the other hand, raised the titers 2- to 8- fold, depending on the pretiters of the individuals. The potency of the same vaccines has been tested using mouse protection experiments: vaccine B gave significantly better protection rates, as measured by survival as well as by reduction of lung lesions. These results give additional evidence that the use of mouse protection experiments for the evaluation of different influenza vaccines is meaningful.