Abstract
The sera of healthy blood donors from the Wellington area of New Zealand, collected between 1976 and 1980, were analysed by the complement fixation test for antibody to Mycoplasma pneumoniae. A high prevalence of antibody to this organism was demonstrated and the occurrence of an M. pneumoniae epidemic in New Zealand within the survey period was shown to be reflected in the immune status of this healthy adult population. This would suggest that during an epidemic many people within the Wellington community may have M. pneumoniae infections involving little overt illness.