Unaltered pneumococcal carriage prevalence due to expansion of non-vaccine types of low invasive potential 8Â years after vaccine introduction in Stockholm, Sweden

The carriage prevalence remained the same 4-8 years after vaccine introduction, but serotype replacement became almost complete. A majority of emerging NVTs in carriage showed a low invasive disease potential. Carriage studies are an important complement to invasive disease surveillance to understand the full effect of PCV vaccine programs.