Brenda Kwambana-Adams, United Kingdom

University College London NIHR Global Health Research Unit on Mucosal Pathogens, Division of Infection & Immunity

Presenter Of 3 Presentations

DECLINING TRENDS IN MENINGITIS AMONG CHILDREN LESS THAN FIVE YEARS OF AGE FOLLOWING THE INTRODUCTION OF THE PNEUMOCOCCAL CONJUGATE VACCINES IN WEST AND CENTRAL AFRICA (ID 973)

Abstract

Background

By 2015, pneumococcal conjugate vaccines (PCVs) had been introduced into the infant immunization programmes of most countries in West and Central Africa. We modelled the trends in meningitis cases and deaths among children before and after PCV introduction.

Methods

A total of 36,901 children under 5 years of age with suspected meningitis were enrolled at sentinel hospitals across 10 West and Central African countries between 2010 and 2016 through the Paediatric Bacterial Meningitis (PBM) Surveillance Network . To assess disease and mortality trends before and after PCV introduction, we applied interrupted time-series models and random effects meta-analysis.

Results

Across the sub-regions, there was a decline of 35% (95% CI 2-57%, p=0.04) in annual suspected meningitis cases and 26% (95% CI 3-44%, p=0.03) in laboratory confirmed meningitis in the post vs. pre-PCV period. Likewise, there was a decreased trend in mortality among suspected meningitis cases (33% decline, 95% CI -23-52%, p=0.27) post PCV introduction. There was considerable heterogeneity among countries with the larger and more precise reduction estimates in countries with >2 years post-PCV surveillance.

meningitis_abstract_1.jpg

Conclusions

We observed significant declines in suspected and confirmed pediatric meningitis across the sub-regions following PCV implementation. Continued monitoring, particularly in countries with more recent PCV introduction is needed.

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ACQUISITION AND CLEARANCE OF PNEUMOCOCCAL SEROTYPES IN NATURALLY-COLONISED PCV-EXPOSED GAMBIAN INFANTS (ID 990)

Abstract

Background

Pneumococcal carriage influences population-wide strain dynamics, but limited data exist on serotype-specific temporal carriage patterns among PCV-vaccinated West African infants.

Methods

Pneumococcus was cultured from nasopharyngeal swabs (n=1, 595) collected from 102 PCV7-exposed infants followed up from birth to 12 months. Serotyping was performed by whole genome sequencing and sweep-latex agglutination. Parametric survival models with constant hazard rates were fitted to estimate carriage dynamics (duration, clearance and acquisition).

Results

The infants were naturally colonised with 60 pneumococcal serotypes with a mean of 7 (range:2-11) serotypes per infant. Carriage dynamics estimates for serotypes 5, 7F, 39, 9A, and 12F are provided here for the first time in infants. There was no correlation between time to first acquisition and carriage duration (ρ=0.06, P=0.709). Serotype prevalence showed a weak correlation with initial acquisition (ρ=0.07, P=0.706), carriage duration (ρ=0.219, P=0.194), and reacquisition times (ρ=0.09, P=0.730). Onset of initial acquisition was longer than the time taken to reacquire serotypes (median: 136.23 vs 26.15 days, P=7.63×10-6). Overall, serotype-specific carriage durations after initial acquisition and reacquisition were significantly different (P=0.020), varying by serotype.

carriage_duration.png

Conclusions

Pneumococcal carriage dynamics among Gambian infants are complex and highly variable by serotype which may have important implications for transmission and invasive disease.

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BIOMASS SMOKE EXPOSURE AND INFLAMMATION ARE ASSOCIATED WITH PNEUMOCOCCAL CARRIAGE AMONG PCV13 VACCINATED INFANTS (ID 983)

Abstract

Background

Despite widespread use of PCV13, pneumococcal carriage remains high among Gambian infants. We investigated the role of biomass smoke exposure and inflammation in modulating pneumococcal carriage in The Gambia.

Methods

Rural Gambian children (n=120) were followed up at regular intervals from birth to two years of age. All infants received PCV13. Pneumococcal carriage was determined by quantitative PCR and inflammation by measuring plasma alpha-1 glycoprotein (AGP). Smoke exposure was self-reported by the mothers. Adjusted random effects regression models were applied to investigate the relationships between pneumococcal carriage, smoke exposure, and inflammation.

Results

Exposure to biomass smoke was significantly associated with a nearly 3-fold increase in the odds of pneumococcal carriage (OR 2.9, 95% CI: 1.13 - 7.5) and, in independent models, a 1/3-log10 increase in pneumococcal load (Coefficient 0.35, 95% CI: 0.11 - 0.59), compared to non-exposure. Inflammation (AGP) was significantly associated with an increased pneumococcal load (Coefficient 0.22, 95% CI: 0.03 - 0.41) in a model unadjusted for smoke exposure. Mediation analysis suggests that there are age, inflammation and smoke exposure interactions that may modify the effects of smoke exposure on pneumococcal carriage.

Conclusions

Biomass smoke exposure may be an important environmental factor driving pneumococcal carriage and loads among PCV-vaccinated Gambian children.

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Author Of 9 Presentations

DECLINING TRENDS IN MENINGITIS AMONG CHILDREN LESS THAN FIVE YEARS OF AGE FOLLOWING THE INTRODUCTION OF THE PNEUMOCOCCAL CONJUGATE VACCINES IN WEST AND CENTRAL AFRICA (ID 973)

Abstract

Background

By 2015, pneumococcal conjugate vaccines (PCVs) had been introduced into the infant immunization programmes of most countries in West and Central Africa. We modelled the trends in meningitis cases and deaths among children before and after PCV introduction.

Methods

A total of 36,901 children under 5 years of age with suspected meningitis were enrolled at sentinel hospitals across 10 West and Central African countries between 2010 and 2016 through the Paediatric Bacterial Meningitis (PBM) Surveillance Network . To assess disease and mortality trends before and after PCV introduction, we applied interrupted time-series models and random effects meta-analysis.

Results

Across the sub-regions, there was a decline of 35% (95% CI 2-57%, p=0.04) in annual suspected meningitis cases and 26% (95% CI 3-44%, p=0.03) in laboratory confirmed meningitis in the post vs. pre-PCV period. Likewise, there was a decreased trend in mortality among suspected meningitis cases (33% decline, 95% CI -23-52%, p=0.27) post PCV introduction. There was considerable heterogeneity among countries with the larger and more precise reduction estimates in countries with >2 years post-PCV surveillance.

meningitis_abstract_1.jpg

Conclusions

We observed significant declines in suspected and confirmed pediatric meningitis across the sub-regions following PCV implementation. Continued monitoring, particularly in countries with more recent PCV introduction is needed.

Hide

BIOMASS SMOKE EXPOSURE AND INFLAMMATION ARE ASSOCIATED WITH PNEUMOCOCCAL CARRIAGE AMONG PCV13 VACCINATED INFANTS (ID 983)

Abstract

Background

Despite widespread use of PCV13, pneumococcal carriage remains high among Gambian infants. We investigated the role of biomass smoke exposure and inflammation in modulating pneumococcal carriage in The Gambia.

Methods

Rural Gambian children (n=120) were followed up at regular intervals from birth to two years of age. All infants received PCV13. Pneumococcal carriage was determined by quantitative PCR and inflammation by measuring plasma alpha-1 glycoprotein (AGP). Smoke exposure was self-reported by the mothers. Adjusted random effects regression models were applied to investigate the relationships between pneumococcal carriage, smoke exposure, and inflammation.

Results

Exposure to biomass smoke was significantly associated with a nearly 3-fold increase in the odds of pneumococcal carriage (OR 2.9, 95% CI: 1.13 - 7.5) and, in independent models, a 1/3-log10 increase in pneumococcal load (Coefficient 0.35, 95% CI: 0.11 - 0.59), compared to non-exposure. Inflammation (AGP) was significantly associated with an increased pneumococcal load (Coefficient 0.22, 95% CI: 0.03 - 0.41) in a model unadjusted for smoke exposure. Mediation analysis suggests that there are age, inflammation and smoke exposure interactions that may modify the effects of smoke exposure on pneumococcal carriage.

Conclusions

Biomass smoke exposure may be an important environmental factor driving pneumococcal carriage and loads among PCV-vaccinated Gambian children.

Hide

ACQUISITION AND CLEARANCE OF PNEUMOCOCCAL SEROTYPES IN NATURALLY-COLONISED PCV-EXPOSED GAMBIAN INFANTS (ID 990)

Abstract

Background

Pneumococcal carriage influences population-wide strain dynamics, but limited data exist on serotype-specific temporal carriage patterns among PCV-vaccinated West African infants.

Methods

Pneumococcus was cultured from nasopharyngeal swabs (n=1, 595) collected from 102 PCV7-exposed infants followed up from birth to 12 months. Serotyping was performed by whole genome sequencing and sweep-latex agglutination. Parametric survival models with constant hazard rates were fitted to estimate carriage dynamics (duration, clearance and acquisition).

Results

The infants were naturally colonised with 60 pneumococcal serotypes with a mean of 7 (range:2-11) serotypes per infant. Carriage dynamics estimates for serotypes 5, 7F, 39, 9A, and 12F are provided here for the first time in infants. There was no correlation between time to first acquisition and carriage duration (ρ=0.06, P=0.709). Serotype prevalence showed a weak correlation with initial acquisition (ρ=0.07, P=0.706), carriage duration (ρ=0.219, P=0.194), and reacquisition times (ρ=0.09, P=0.730). Onset of initial acquisition was longer than the time taken to reacquire serotypes (median: 136.23 vs 26.15 days, P=7.63×10-6). Overall, serotype-specific carriage durations after initial acquisition and reacquisition were significantly different (P=0.020), varying by serotype.

carriage_duration.png

Conclusions

Pneumococcal carriage dynamics among Gambian infants are complex and highly variable by serotype which may have important implications for transmission and invasive disease.

Hide

TRANSMISSION OF THE PNEUMOCOCCUS BETWEEN MOTHER AND NEWBORN IN THE GAMBIA (ID 1195)