Second attacks of pneumonia due to Mycoplasma pneumoniae.

Long-term surveillance of pneumonia in a group that received prepaid medical care disclosed five cases of pneumonia due to Mycoplasma pneumoniae that recurred in immunocompetent persons after a lapse of two and one-half to 10 years. Diagnosis was confirmed by isolation of M. pneumoniae, by observation of changes in titer of antibody, and by chest films. In addition, a patient with a variable immunodeficiency syndrome that affected the bone marrow-derived (B-) cell system had recurrent infection with M. pneumoniae within a one-year interval. Naturally acquired immunity to infection with M. pneumoniae appears to be of limited duration.