Prevalence of antibodies to Chlamydia pneumoniae TWAR in a group of German medical students.

Prevalence of antibodies to Chlamydia pneumoniae TWAR in Germany has not been previously evaluated. Therefore a healthy adult population of 353 German medical students (mean age 24 years) was examined with a species-specific microimmunofluorescence test for IgG, IgM and IgA antibodies to C. pneumoniae and in parallel to Chlamydia trachomatis. Altogether, 229 persons had IgG antibodies to C. pneumoniae (64.9%), 136 had IgA antibodies (38.5%), while the serum of only one contained specific IgM. Prevalence rates were higher in males (69.4%) than in females (57.3%). The total prevalence for antibodies to C. trachomatis was 5.9%. The results indicate that C. pneumoniae infections are highly endemic in Germany, and that primary infection probably takes place in children or young adults. Prevalence of antibodies to C. pneumoniae in this group of healthy young adults was about 10-fold higher than that to C. trachomatis. This finding needs to be taken into account when genus-specific tests are used for studying Chlamydial antibodies.