Human Influenza Resulting from Aerosol Inhalation

Summary Volunteers were given A2 influenza virus in a small-particle aerosol. Infection and typical influenza resulted from low doses of virus administered in this manner. Low levels of serum neutralizing antibody were not completely effective in preventing infection and illness. The human infectious dose of this influenza strain when administered by aerosol to subjects free of serum neutralizing antibody was approximately 3 TCID50. Gratitude is expressed to Dr. David W. Ailing for assistance with the statistics and in calculating dosages; Mr. Edward W. Harvey, Mr. Irven B. Stacy, Mr. Leonard P. Durocher, and Mr. James Turner for technical assistance; and Mr. Edward P. Derren-bacher aand Mr. Charles O. Masemore for assistance with volunteer inoculations.