Production of common colds in human volunteers by influenza C virus

Influenza C virus was intranasally administered to volunteers; most were infected and nine developed symptoms of common cold.Increasing titres of serum haemagglutination-inhibiting antibody and complement-fixing antibody were detected. Virus neutralizing activity in nasal secretion was not correlated with either resistance to infection or the occurrence of overt illness. Interferon was detected in the nasal secretions of some subjects.