A 13-year survey of pneumococcal nasopharyngeal carriage in children with acute otitis media following PCV7 and PCV13 implementation.Vaccine 2015; 33(39):5118-26V
This nasopharyngeal (NP) carriage surveillance study was requested by the European Agency for the Evaluation of Medicinal Products as a post-licensing commitment to determine whether the use of the pneumococcal conjugate vaccines (PCVs) including 7 then 13 valents (introduced in 2001 and 2010, respectively) caused a shift in the distribution of Streptococcus pneumoniae serotypes in children with acute otitis media and modified the resistance of this bacterial species to antibiotics.
Between 2001 and 2014, 121 pediatricians obtained nasopharyngeal swabs from children with acute otitis media aged 6-24 months. The swabs were analyzed by the French National Reference Centre for Pneumococci. Demographics, medical history and physical examination findings were recorded.
Over the 13 years, among the 7991 enrolled patients, the proportion of PCV-vaccinated children (≥1 dose) increased (54.3-99.7%, p<0.001). Overall, pneumococcal carriage was reduced from 71.2% to 56.2% from 2001 to 2014 (p<0.001) and carriage of PCV7 serotypes (STs) from 44.5% to 1.2% (p<0.001). The carriage of 6 additional STs plus 6C increased from 17.2% to 24.3% from 2001 to 2010 (p<0.001) and decreased after PCV13 implementation (21.4-3.5%, p<0.001). The proportion of ST 19A carriage increased from 8.6% to 15.8% from 2001 to 2010 (p<0.001) and decreased to 1.2% in 2014. After PCV13 implementation, the most frequently carried non-PCV13 STs were ST 15B/C, 11A, 15A, and 35B. Penicillin non-susceptible pneumococcal strains decreased from 67.1% in 2001 to 33.1% in 2014 (p<0.001).
By the number of patients enrolled and the duration, this study is the largest performed to date. It allows to demonstrate a strong impact of PCVs and to describe the complex dynamics of pneumococcal carriage during AOM. As pneumococcal carriage decreased during AOM, a reduction in the incidence of pneumococcal AOM could be expected.