Direct and indirect effects of the 13-valent pneumococcal conjugate vaccine administered to infants and young children.

This paper analyzes the most recent reports regarding the direct and indirect effects of the 13-valent pneumococcal conjugate vaccine (PCV13) when administered to infants and young children. PCV13 extends the protective effects reported for the 7-valent pneumococcal conjugate vaccine (PCV7). A further reduction in the incidence of invasive pneumococcal disease, community-acquired pneumonia, acute otitis media, rhinosinusitis and carriage of PCV13 serotypes in vaccinated and unvaccinated subjects was found with PCV13 compared with PCV7. However, further studies are required to establish the effectiveness of PCV13 against serotypes 1, 5 and 3, the role of cross-protective antibodies evoked by serotype 6A on serotype 6C and the importance of the serotype replacement phenomenon following the extension of PCV13 use.