Prevalence of Chlamydia pneumoniae in healthy children and in children with respiratory tract infections

Background. Chlamydia pneumoniae causes respiratory tract infections in adults, but little is known about its significance for acute or persistent respiratory tract infections in children. Methods. We studied the prevalence of C. pneumoniae by polymerase chain reaction in children younger than the age of 11: 85 consecutive children with respiratory tract infections; and 93 children presumed to be healthy. Throat swabs for PCR analysis were taken from all children, and serology was done for 54 of the 85 sick children and from all but one of the presumed healthy children positive for C. pneumoniae by PCR. Results. PCR was positive in 38 (45%) of the sick children and in 5 (5.7%) of the healthy children. All but 2 of 19 sick children with serologic findings suggesting recent or ongoing infection with C. pneumoniae were positive by PCR. Most children positive for C. pneumoniae by PCR had upper respiratory tract infections. Four children had recurrent respiratory tract infections and otitis media with effusion treated by tubal insertion. Conclusion. The findings suggest that C. pneumoniae is common among children with respiratory tract infections.