Ifedayo.M.O Adetifa, Kenya
KEMRI-Wellcome Trust Research Programme,Kilifi Epidemiology and DemographyPoster Author Of 1 e-Poster
EARLY IMPACT OF INTRODUCING A TEN-VALENT PNEUMOCOCCAL CONJUGATE VACCINE (PCV10) ON PNEUMOCOCCAL CARRIAGE IN NIGERIA
Author Of 3 Presentations
LONG-TERM TRENDS IN NASOPHARYNGEAL CARRIAGE OF VACCINE-TYPE PNEUMOCOCCI: FINDINGS FROM A MATURE 10-VALENT PNEUMOCOCCAL CONJUGATE VACCINE (PCV10) PROGRAM IN KENYA (ID 966)
Abstract
Background
PCV10 was introduced into Kenya’s immunization program in 2011, with catchup in children aged 1-4 years. We evaluated the long-term effect of PCV10 on nasopharyngeal carriage of Streptococcus pneumoniae serotypes included in PCV10.
Methods
Population-based annual cross-sectional nasopharyngeal carriage surveys were conducted in randomly selected individuals between 2009 and 2019 (N= ~1000 in 2019; N= ~500 in all others) in Kilifi, Kenya. Pneumococcal identification was performed per WHO standards. Annual vaccine-type carriage prevalence was modelled using log-binomial regression with a curved function for year and adjustment for age-specific sampling probability.
Results
Compared to 2010, carriage of PCV10-type pneumococci declined significantly through 2019 in children aged <5 years to 6.1% (adjusted prevalence ratio 0.18, 95%CI 0.11-0.30) but not in children aged 5-14 years (prevalence= 7.1%; 0.71, 0.38-1.34) nor adults ≥15 years (prevalence= 1.0%; 0.49, 0.17-1.35). PCV10-type carriage was significantly lower in 2017 compared to 2010 for all age groups and did not differ from carriage prevalence in 2019 (figure).
Conclusions
PCV10-type carriage prevalence appears to be approaching equilibrium, yet residual carriage persists. Virtual elimination of PCV10-type carriage (≤1% in children <5 years; ≤3% in children 5-9 years) – a prerequisite for introduction of reduced dose schedules – is unlikely without implementation of additional strategies.
ANTIMICROBIAL RESISTANCE PATTERNS IN PNEUMOCOCCAL CARRIAGE PRE AND POST PCV10 INTRODUCTION IN NIGERIA (ID 521)
Abstract
Background
Pneumococcal conjugate vaccines (PCVs) reduce antimicrobial resistance (AMR). In Africa, where disease surveillance is limited, nasopharyngeal carriage studies may reveal PCV impact on AMR . We investigated AMR in pneumococcal carriage in Nigeria.
Methods
Nigeria introduced PCV10 between 2014-2016. Random carriage surveys targeting 1000 participants were conducted pre-(2016) and post-PCV10 (2017-2018) in two locations (rural and urban). PCV10 coverage in 2017 and 2018 was 47% and 55%, respectively. Isolates randomly selected from each survey were tested for antimicrobial resistance using broth micro-dilution.
Results
In 571 pneumococcal isolates, prevalence of resistance was -Tetracycline (69%), Cotrimoxazole (68%), Penicillin (43%) and Chloramphenicol (14%). Serotypes 19F, 6A, 11A, 23F, 3, 16F, 19A, 34 and 6B had a high prevalence of resistance. Prevalence of resistance to any antibiotic differed little by pre- vs post-PCV10 era both overall (86% and 85%) and in rural (73% and 71%) and urban (99% and 98%) samples. No difference was seen in prevalence of resistance among vaccine and non-vaccine serotypes by PCV10 era.
Conclusions
Among healthy Nigerians, prevalence of resistance to commonly used antibiotics is high in carried pneumococci. Although the data do not show any impact of PCV10 on resistance prevalence, the lack of effect may be explained by incomplete coverage levels.
EARLY IMPACT OF INTRODUCING A TEN-VALENT PNEUMOCOCCAL CONJUGATE VACCINE (PCV10) ON PNEUMOCOCCAL CARRIAGE IN NIGERIA (ID 652)
Abstract
Background
As Nigeria transitions from Gavi-support to self-financing of the pneumococcal conjugate vaccine (PCV), decisions on vaccine cost effectiveness should be based on local vaccine impact data. Herd immunity against carriage is a major contributor to PCV impact. So, carriage surveys are a useful option for impact assessments in the absence of disease surveillance systems.
Methods
We conducted nasopharyngeal carriage surveys (2017-2019) according to WHO guidelines among randomly selected residents of two locations (urban and rural) in Nigeria. PCV10 was introduced in 2016 in these locations and reached a modest coverage of 37% and 61% by 2019. Carriage prevalence ratios (PR) before and after PCV10 introduction were estimated using log-binomial regression.
Results
There was a 38% (PR-0.62 [95%CI:0.53-0.72]) and 21% (PR-0.79 [95%CI:0.66-0.94]) reduction in carriage of vaccine serotypes respectively among vaccine-target (<5years) and non-target) (5+ years) groups, mostly due to serotypes 19F, 23F and 6B. Carriage of non-vaccine serotypes increased by 28% (PR-1.28 [95%CI:1.15-1.42]) and 31% (PR-1.31 [95%CI:1.20-1.43]) respectively in these groups; serotypes 6A, 19A, 34, 16F and 11A were prominent.
Conclusions
Within three years of PCV10 introduction, we found early evidence of direct and indirect PCV effects on vaccine serotype carriage as well as serotype replacement in carriage.