[Determination of the degree of antigenic novelty and of the epidemic currency of influenza virus strains].

A simple, practically feasible method based on neutralization of viruses with antibodies present in pools of placental immunoglobulin followed by their reactivation from the complex has been proposed for objective evaluation of the protection of the population against circulating variants of influenza virus and preliminary assessment of their antigenic novelty. The data obtained by this method show that the study may be done within a comparatively short period and will give an objective evaluation of the antigenic novelty and epidemic importance of various influenza virus strains with reference to the immunological status of the population in a definite region which permits one not only to determine the epidemic hazard of the strains for the present time but also to prognosticate it for the future.