PCV13 serotype decrease in Italian adolescents and adults in the post-PCV13 era: Herd protection from children or secular trend?

Our study demonstrated a difference in percentage in serotype distribution in adolescents and adults laboratory-confirmed pneumococcal infection between the pre and post-PCV13 eras. This difference is mainly due to the decrease of serotype 7F. Thus, in order to decrease disease burden, adults and in particular the elderly should be offered a specific vaccination program.