Impact of 13-valent pneumococcal conjugate vaccine on pneumococcal nasopharyngeal carriage in children with acute otitis media.

BACKGROUND: 13-valent pneumococcal conjugate vaccine (PCV13) licensure was based on the immune response (enzyme-linked immunosorbent assay and opsonophagocytic assay) compared with PCV7. National surveillance program of pneumococcal nasopharyngeal (PNP) carriage in children with acute otitis media (AOM) was set up in 2001 when PCV7 was introduced in France and continues to the present. This program was used in 2010-2011 to assess the effect of the implementation of PCV13 on PNP carriage in young children with AOM.

METHODS: Between October 2010 and March 2011, 58 pediatricians obtained 943 nasopharyngeal swabs from children (6 to 24 months of age) with AOM. The swabs were sent for analysis to the French National Reference Centre for Pneumococci. Demographics, medical history, and physical examination findings were recorded.

RESULTS: Among 943 children enrolled (mean age, 13.4 months), 651 had received at least 1 dose of PCV13 and 285 received PCV7 only. Among PCV13-vaccinated children, overall PNP carriage and carriage of serotypes not in PCV7 were significantly lower as compared with children exclusively vaccinated with PCV7 (53.9% vs. 64.6%, P = 0.002 and 9.5% vs. 20.7%, P < 0.0001, respectively). For serotypes 19A, 7F, and 6C, the carriage rates were also significantly lower in PCV13-vaccinated patients than in patients only vaccinated by PCV7: 7.5% versus 15.4%, P < 0.001, 0.5% versus 2.8%, P = 0.002, and 3.7% versus 8.4%, P = 0.003, respectively.

CONCLUSION: In young children (<2 years) with AOM, this study suggests that PCV13 has an impact on overall PNP carriage, as well as on serotypes 19A, 7F, and 6C.