Key Points

• The introduction of the PCV13 vaccine into the infant immunization schedule was followed by a decrease in invasive pneumococcal infections among children under 2 years of age targeted by vaccination recommendations, and, through herd immunity, also among older children and adults.

• However, this decrease remains moderate to date, given the very high vaccination coverage achieved among infants (92% in 2017 for the 11-month booster dose). This situation is due to the combination of two opposing phenomena: on the one hand, a significant decline in cases of invasive pneumococcal infections caused by the 6 additional serotypes of PC13, coupled with a continued decrease in cases caused by the 7 serotypes covered by the two vaccines, PC7 and PC13; and, on the other hand, the induction, since the introduction of pneumococcal vaccination, of a serotype replacement phenomenon that has led to an increase in cases caused by strains of serotypes not covered by PC13. Although this phenomenon remains limited to date and does not call into question the benefits of vaccination, it is being closely monitored.

• Compared with 2017 data, the 2018 data indicate a stable incidence of invasive pneumococcal infections, following an upward trend observed between 2015 and 2016. This trend was particularly pronounced among children under 2 years of age and adults. It was primarily linked to an increase in the incidence of several serotypes not included in the 13-valent pneumococcal conjugate vaccine (PCV13) (notably serotypes 12F, 8, 22F in adults, and serotype 24F in children) and marked a break from the steady decline observed since the introduction of PCV13 in 2010.