Key Points

• Compared with 2018 data, the 2019 data indicate a continuation of the upward trend in the incidence of invasive pneumococcal infections observed since 2015. This trend was observed among children under 2 years of age, those aged 5–14 years, and adults aged 65 years and older. It was primarily linked to the increased incidence of several serotypes not included in the 13-valent pneumococcal conjugate vaccine (PCV13) (notably serotypes 8, 12F, and 22F in adults, and serotype 24F in children) and to serotype 3, which is included in PCV13.

• The introduction of the PCV13 vaccine into the infant immunization schedule in 2010 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 has been followed by an upward trend since 2015. 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 strains of the 6 additional serotypes in PC13, associated with a continued decline in cases caused by the 7 serotypes covered by both the PC7 and PC13 vaccines; 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 PCV13.

• Although this phenomenon does not call into question the benefits of vaccination to date, it is being closely monitored. The use of the two new vaccines (PCV15 (PCV13 + 22F and 33F) and PCV20 (PCV13 + 8, 10A, 11A, 12F, 15B, 22F, 33F)) in the coming years could reverse the upward trend in the incidence of invasive pneumococcal infections observed since 2015.