Impact of 13-Valent Pneumococcal Conjugate Vaccine on Pneumococcal Meningitis, Burkina Faso, 2016–2017

Abstract

Background In 2013, Burkina Faso introduced 13-valent pneumococcal conjugate vaccine (PCV13) into the routine childhood immunization program, to be administered to children at 8, 12, and 16 weeks of age. We evaluated the impact of PCV13 on pneumococcal meningitis. Methods Using nationwide surveillance, we gathered demographic/clinical information and cerebrospinal fluid (CSF) results for meningitis cases. Pneumococcal cases were confirmed by culture, polymerase chain reaction (PCR), or latex agglutination; strains were serotyped using PCR. We compared annual incidence (cases per 100 000) 4 years after PCV13’s introduction (2017) to average pre-PCV13 incidence (2011–2013). We adjusted incidence for age and proportion of cases with CSF tested at national laboratories. Results In 2017, pneumococcal meningitis incidence was 2.7 overall and 10.5 (<1 year), 3.8 (1–4 years), 3.5 (5–14 years), and 1.4 (≥15 years) by age group. Compared to 2011–2013, PCV13-serotype incidence was significantly lower among all age groups, with the greatest decline among children aged <1 year (77%; 95% confidence interval [CI], 65%–84%). Among all ages, the drop in incidence was larger for PCV13 serotypes excluding serotype 1 (79%; 95% CI, 72%–84%) than for serotype 1 (52%; 95% CI, 44%–59%); incidence of non-PCV13 serotypes also declined (53%; 95% CI, 37%–65%). In 2017, 45% of serotyped cases among all ages were serotype 1 and 12% were other PCV13 serotypes. Conclusions In Burkina Faso, meningitis caused by PCV13 serotypes continues to decrease, especially among young children. However, the concurrent decline in non-PCV13 serotypes and short pre-PCV13 observation period complicate evaluation of PCV13’s impact. Efforts to improve control of serotype 1, such as switching from a 3 + 0 schedule to a 2 + 1 schedule, may improve overall control of pneumococcal meningitis in this setting.

Evaluation of pneumococcal meningitis clusters in Burkina Faso and implications for potential reactive vaccination

“… Note: Some of the data presented in this table have been previously published [15] . Abbreviations: CSF, cerebrospinal fluid; PCR, polymerase chain reaction; PCV13, 13-valent pneumococcal conjugate vaccine.…”

“…One potential prevention tool that has been discussed to further reduce pneumococcal meningitis is to strive for better control of all invasive pneumococcal infections by adding a booster dose to the infant vaccination series [15] , [37] . The WHO currently recommends both PCV booster-containing schedules (2 primary doses and 1 booster dose at 9–12 months of age: 2 + 1) and non-booster-containing schedules (3 primary doses: 3 + 0) [38] .…”

“…However, the decline in incidence was larger for PCV13 serotypes excluding serotype 1 (79% reduction) than for serotype 1 (52% reduction). These data suggested impact of PCV13, but that efforts to improve control of serotype 1, such as switching from a 3 + 0 schedule to a 2 + 1 schedule, may improve overall control of pneumococcal meningitis in this setting [15] , [19] .…”

“…The WHO-UNICEF estimate of vaccination coverage with 3 doses of PCV13 in Burkina Faso was 91% for 2014–2017 [14] . Burkina Faso is one of the few African countries to both successfully implement nationwide case-based meningitis surveillance and to also routinely serotype all pneumococcal meningitis specimens, in an effort to evaluate PCV13 impact [9] , [15] , [16] , [17] , [18] .…”

“…Before PCV13 introduction in Burkina Faso, the highest pneumococcal meningitis incidence and mortality occurred among children aged < 1 year, and 71% of cases were due to PCV13 serotypes [18] . In the first 4 years after nationwide PCV13 introduction, meningitis due to PCV13-serotypes declined substantially (62%), both among vaccinated age groups (children aged < 1 year: 77% reduction) and among older age groups potentially benefitting from herd protection (persons aged ≥ 15 years: 64% reduction) [15] , [16] . However, the decline in incidence was larger for PCV13 serotypes excluding serotype 1 (79% reduction) than for serotype 1 (52% reduction).…”