Apolyvalent vaccine using only the active fraction of the influenza virus appears to be more potent and have lower toxicity than the standard whole virus preparations, two investigators at the University of Michigan report.
The vaccine even appears to be well-tolerated by infants. Standard influenza vaccine is usually not recommended in very young children because of its toxic effects.
Comparison of the whole virus vaccines and a vaccine containing purified hemagglutinating subunits was made by Fred M. Davenport, MD, and Albert V. Hennessy, MD. The results were reported to the annual meeting in Los Angeles of the American Society for Microbiology.
Aqueous vaccines were prepared containing the equivalent of 1,000 chick-cell agglutination (CCA) units of either intact virus or hemagglutinins. Mineral oil adjuvant vaccines containing one eighth these amounts (125 CCA units) were also tested.
Relative antigenic potency was determined by comparing levels of hemagglutination inhibition antibodies in sera from