During an etiology study of adults hospitalized for pneumonia, in which urine specimens were examined for serotype-specific pneumococcal antigen detection, we observed that some patients received 23-valent pneumococcal polysaccharide vaccine before urine collection. Some urine samples became positive for specific vaccine pneumococcal serotypes shortly after vaccination, suggesting false-positive test results.
Keywords: antigen; pneumococcal conjugate vaccine; pneumonia; serotype; urine.