The purpose of this study is to assess the direct effects of the ten-valent pneumococcal conjugate vaccine administered to infants on nasopharyngeal carriage at 3 to 5 years of age.

These children have been vaccinated in infancy in the cluster-randomized Finnish Invasive pneumococcal Disease (FinIP) Trial (a separate protocol reported at ClinicalTrials.gov Identifier:NCT00861380) during 2009 to 2011.

Also the indirect effect on nasopharyngeal carriage will be assessed on vaccinees' elder non-vaccinated siblings aged 5 to 9 years.

This study includes a cross-sectional sampling of nasopharyngeal and oropharyngeal swabs in 2013 from vaccinated and unvaccinated children.

Inclusion Criteria for FinIP-vaccinated children:

1. age 3 to 5 years
2. enrolled in the FinIP trial and has received at least one dose of study vaccine in the infant vaccine schedule (3+1 or 2+1)
3. at least one parent with fluent Finnish
4. informed consent from one parent

Exclusion criteria for FinIP-vaccinated children

1. PCV vaccination administered, other than the randomized study vaccine
2. history of antimicrobial treatment within 4 weeks (the child can be enrolled later)

Inclusion criteria for unvaccinated siblings

1. age 5 to 9 years
2. younger sibling living in the same household having participated in the FinIP trial (regardless of the vaccination schedule)
3. at least one parent with fluent Finnish
4. informed consent from one parent

Exclusion criteria for unvaccinated siblings

1. PCV vaccination administered
2. history of antimicrobial treatment within 4 weeks (the child can be enrolled later)

Children vaccinated in infancy in the cluster-randomized Finnish Invasive pneumococcal Disease (FinIP) Trial (ClinicalTrials.gov Identifier:NCT00861380) during 2009 to 2011 and their unvaccinated older siblings.