Reactivation of Serum Neutralized Influenza Virus and Failure of its Use in Primary Isolation

Abstract

Summary

1. Inactivated viruses of 4 strains of influenza A and 2 strains of influenza B reactivated serum neutralized homologous virus with an increase in titer of 100 fold or more. The reaction is serologically strain specific. 2. The degree of reactivation is dependent on time of addition of inactivated virus to active virus-antiserum mixture. The threshold time after which reactivation could not be noted was about 8 hours for A/Va/1/53 and about 3 hours for B/Lee. 3. Addition of concentrated, heat-inactivated virus to samples from throats of persons ill with influenza-like illness during an influenza epidemic failed to increase the number of influenza virus isolations over the usual method.