Seven-valent pneumococcal conjugate vaccine and nasopharyngeal microbiota in healthy children.

Seven-valent pneumococcal conjugate vaccine (PCV-7) is effective against vaccine serotype disease and carriage. Nevertheless, shifts in colonization and disease toward nonvaccine serotypes and other potential pathogens have been described. To understand the extent of these shifts, we analyzed nasopharyngeal microbial profiles of 97 PCV-7-vaccinated infants and 103 control infants participating in a randomized controlled trial in the Netherlands.