IN SELECTING the kind of influenza virus vaccine to be used in the immunization of children, it appeared necessary that consideration be given the advantages and disadvantages, if any, of the various kinds of vaccine available.
At the time this study was undertaken there were four kinds of influenza virus vaccine which had been recommended for clinical use. All were prepared from the allantoic fluid of chick embryos infected with influenza virus, and all contained 50 per cent type A (half PR8 strain and half Weiss strain) and 50 per cent type B (Lee strain) viruses. Both types were included because they do not cross immunize. These four kinds of vaccine differed in the way the allantoic fluid was processed, as follows:
One kind of vaccine, commonly called the eluate vaccine,1 was prepared by adsorbing the virus onto chick embryo red blood cells and subsequently eluting the virus