Impact of 13-Valent Pneumococcal Conjugate Vaccine on Meningitis and Pneumonia Hospitalizations in Children aged <5 Years in Senegal, 2010-2016.

Background. Senegal introduced a 13-valent pneumococcal conjugate vaccine (PCV13) in October 2013, given at 6, 10, and 14 weeks of age. We document trends of meningitis and pneumonia after the PCV13 introduction. Methods. From October 2010-October 2016, hospitalization data for clinical meningitis and pneumonia in children aged <5 years were collected from logbooks at a large, tertiary, pediatric hospital in Dakar. We used a set of predetermined keywords to define hospitalizations for extraction from hospital registers. We conducted a time-series analysis and compared hospitalizations before and after the PCV13 introduction, accounting for seasonality. The initial PCV13 uptake period (October 2013-September 2014) was considered to be transitional and was excluded. Results. Over the 7-year period, 1836 and 889 hospitalizations with a discharge diagnosis of pneumonia and meningitis, respectively, occurred in children aged <5 years. In children aged <12 months, a small, significant reduction in pneumonia was observed post-PCV13 (-3.8%, 95% confidence interval [CI] -1.5 to -5.9%). No decline was observed among children aged 12-59 months (-0.7%, 95% CI -0.8 to 2.2%). Meningitis hospitalizations remained stable for children aged <12 months (1.8%, 95% CI -0.9 to 4.4%) and 12-59 months (-0.5%, 95% CI -3.6 to 2.6%). Conclusions. We used data from 1 hospital to detect a small, significant reduction in all-cause pneumonia hospitalizations 2 years post-PCV13 introduction in infants; the same trend was not measurable in children aged 12-59 months or in meningitis cases. There is a need for continued surveillance to assess the long-term impact of sustained PCV13 use and to monitor how pneumococcus is causing disease in the meningitis belt.