Prevalence of pneumococcal nasopharyngeal colonization and serotypes circulating in Cameroonian children after the 13-valent pneumococcal conjugate vaccine introduction

International Journal of Infectious Diseases

Arto A. Palmu¹  Maija Toropainen²  Kirsi Gröndahl-Yli-Hannuksela³  Sinata Koulla-Shiro⁴  Marie Kobela⁵  Paul Koki Ndombo⁶  John Njuma Libwea⁷  Outi Nyholm⁸  Jaana Vuopio⁹  J. Pekka Nuorti^1,10  Hanna Nohynek^1,10 

[1] Child Center (MCH), Chantal Biya Foundation, Yaoundé, Cameroon;Corresponding author at: Health Sciences Unit, Faculty of Social Sciences, Tampere University, Finland.;Expanded Programme on Immunization, Cameroon;Faculty of Medicine and Biomedical Sciences, University of Yaoundé 1, Cameroon;National Institute for Health and Welfare (THL), Finland;Expanded Programme on Immunization, Cameroon;Health Sciences Unit, Faculty of Social Sciences, Tampere University, Finland;Institute of Biomedicine, Research Center for Cancer, Infections and Immunity, University of Turku, Finland;;Mother &National Institute for Health and Welfare (THL), Finland;

关键词: Nasopharyngeal carriage;    Streptococcal pneumoniae;    Cameroon;    Serotypes;    Pneumococcal conjugate vaccines;   

DOI  :  

来源: DOAJ

【 摘 要 】

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: 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: 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: 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.

【 授权许可】

Unknown