Prevalence of pneumococcal nasopharyngeal colonization and serotypes circulating in Cameroonian children after the 13-valent pneumococcal conjugate vaccine introduction.
Cameroon
/ epidemiology
Carrier State
/ epidemiology
Child, Preschool
Cross-Sectional Studies
Female
Humans
Immunization Programs
Immunization Schedule
Male
Nasopharynx
/ microbiology
Pneumococcal Infections
/ epidemiology
Pneumococcal Vaccines
/ administration & dosage
Prevalence
Serogroup
Serotyping
Streptococcus pneumoniae
/ genetics
Vaccination
Cameroon
Nasopharyngeal carriage
Pneumococcal conjugate vaccines
Serotypes
Streptococcal pneumoniae
Journal
International journal of infectious diseases : IJID : official publication of the International Society for Infectious Diseases
ISSN: 1878-3511
Titre abrégé: Int J Infect Dis
Pays: Canada
ID NLM: 9610933
Informations de publication
Date de publication:
Sep 2020
Sep 2020
Historique:
received:
02
04
2020
revised:
14
06
2020
accepted:
15
06
2020
pubmed:
21
6
2020
medline:
27
10
2020
entrez:
21
6
2020
Statut:
ppublish
Résumé
Streptococcus pneumoniae remains a major contributor to childhood infections and deaths globally. In Cameroon, the 13-valent pneumococcal conjugate vaccine (PCV13) was introduced in July 2011, using a 3-dose Expanded programme on immunization (EPI) schedule administered to infants at 6, 10 and 14 weeks of age. To evaluate PCV13 effects, we assessed pneumococcal nasopharyngeal colonization and serotype distribution among Cameroonian children after PCV13 introduction. Nasopharyngeal (NP) swabs were collected from eligible children aged 24-36 months in two cross-sectional surveys conducted from March to July: in 2013 (PCV13-unvaccinated), and in 2015 (PCV13-vaccinated). Using a systematic World Health Organization (WHO) cluster coverage sampling technique in 40 communities, NP swabs collected were processed following WHO recommendations. Standard bacterial culture techniques were used for the isolation of S. pneumoniae from gentamicin-blood agar plates and identification using optochin susceptibility testing. Serotyping was performed using sequential multiplex polymerase chain reaction, supplemented with Quellung test. Among the PCV13-vaccinated children, overall pneumococcal carriage prevalence was 61.8% (426/689) and PCV13 vaccine-type carriage prevalence was 18.0% (123/689). Eleven out of the 13 vaccine serotypes were detected in the vaccinated children. The most common serotypes were 19F (4.5%, 31/689) and 15B/C (7.3%, 50/689). In Cameroon, four years after infant vaccination nearly all of the PCV13-serotypes continued to circulate in the population. This suggests that the direct and indirect effects of the vaccination programme have not resulted in expected low levels of vaccine-type transmission. Continuous monitoring is needed to assess the long term effects of the PCV13 on nasopharyngeal carriage and disease.
Sections du résumé
BACKGROUND
BACKGROUND
Streptococcus pneumoniae remains a major contributor to childhood infections and deaths globally. In Cameroon, the 13-valent pneumococcal conjugate vaccine (PCV13) was introduced in July 2011, using a 3-dose Expanded programme on immunization (EPI) schedule administered to infants at 6, 10 and 14 weeks of age. To evaluate PCV13 effects, we assessed pneumococcal nasopharyngeal colonization and serotype distribution among Cameroonian children after PCV13 introduction.
METHODS
METHODS
Nasopharyngeal (NP) swabs were collected from eligible children aged 24-36 months in two cross-sectional surveys conducted from March to July: in 2013 (PCV13-unvaccinated), and in 2015 (PCV13-vaccinated). Using a systematic World Health Organization (WHO) cluster coverage sampling technique in 40 communities, NP swabs collected were processed following WHO recommendations. Standard bacterial culture techniques were used for the isolation of S. pneumoniae from gentamicin-blood agar plates and identification using optochin susceptibility testing. Serotyping was performed using sequential multiplex polymerase chain reaction, supplemented with Quellung test.
RESULTS
RESULTS
Among the PCV13-vaccinated children, overall pneumococcal carriage prevalence was 61.8% (426/689) and PCV13 vaccine-type carriage prevalence was 18.0% (123/689). Eleven out of the 13 vaccine serotypes were detected in the vaccinated children. The most common serotypes were 19F (4.5%, 31/689) and 15B/C (7.3%, 50/689).
CONCLUSION
CONCLUSIONS
In Cameroon, four years after infant vaccination nearly all of the PCV13-serotypes continued to circulate in the population. This suggests that the direct and indirect effects of the vaccination programme have not resulted in expected low levels of vaccine-type transmission. Continuous monitoring is needed to assess the long term effects of the PCV13 on nasopharyngeal carriage and disease.
Identifiants
pubmed: 32562849
pii: S1201-9712(20)30483-5
doi: 10.1016/j.ijid.2020.06.048
pii:
doi:
Substances chimiques
13-valent pneumococcal vaccine
0
Pneumococcal Vaccines
0
Types de publication
Journal Article
Langues
eng
Sous-ensembles de citation
IM
Pagination
113-120Informations de copyright
Copyright © 2020 The Authors. Published by Elsevier Ltd.. All rights reserved.