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.