Attenuated influenza produced by experimental intranasal inoculation.

To assess the relative effect of natural versus experimental influenza illness on pulmonary function, we compared 43 normal adults with documented nonpneumonic influenza A infection during three outbreaks, 1974 (A/Port Chalmers/74), 1975 (A/Port Chalmers/74), and 1976 (A/Victoria/75) to 24 normal volunteers following nasal inoculation with wild-type influenza A/England/42/72, A/Scotland/74 or A/Victoria/75. In naturally acquired illness, abnormalities in small airway functiion and transiently increase airway reactivity were observed. In contrast, no such dysfunction was observed in experimentally induced illness. This group manifested milder illness and significantly shorter duration of cough.