Pneumococcal carriage in children in Ulaanbaatar, Mongolia before and one year after the introduction of the 13-valent pneumococcal conjugate vaccine.

This study demonstrates substantive PCV13 impact on pneumococcal carriage one year post-vaccine introduction in Mongolia. The reductions in PCV13 serotype carriage are likely to result in reductions in pneumococcal disease including indirect effects. Increases in non-PCV13 serotypes require further monitoring.