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Prevalence of pneumococcal nasopharyngeal colonization and serotypes circulating in Cameroonian children after the 13-valent pneumococcal conjugate vaccine introduction.
Int J Infect Dis. 2020 Sep; 98:113-120.IJ

Abstract

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.

Authors+Show Affiliations

Health Sciences Unit, Faculty of Social Sciences, Tampere University, Finland; Expanded Programme on Immunization, Cameroon; National Institute for Health and Welfare (THL), Finland. Electronic address: libwea_j@yahoo.com.Institute of Biomedicine, Research Center for Cancer, Infections and Immunity, University of Turku, 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.National Institute for Health and Welfare (THL), Finland.Mother & Child Center (MCH), Chantal Biya Foundation, Yaoundé, Cameroon; Faculty of Medicine and Biomedical Sciences, University of Yaoundé 1, Cameroon.Faculty of Medicine and Biomedical Sciences, University of Yaoundé 1, Cameroon; Ministry of Public Health, Yaoundé, Cameroon.Health Sciences Unit, Faculty of Social Sciences, Tampere University, Finland; National Institute for Health and Welfare (THL), Finland.Health Sciences Unit, Faculty of Social Sciences, Tampere University, Finland; National Institute for Health and Welfare (THL), Finland.Institute of Biomedicine, Research Center for Cancer, Infections and Immunity, University of Turku, Finland.Health Sciences Unit, Faculty of Social Sciences, Tampere University, Finland; National Institute for Health and Welfare (THL), Finland.

Pub Type(s)

Journal Article

Language

eng

PubMed ID

32562849

Citation

Njuma Libwea, John, et al. "Prevalence of Pneumococcal Nasopharyngeal Colonization and Serotypes Circulating in Cameroonian Children After the 13-valent Pneumococcal Conjugate Vaccine Introduction." International Journal of Infectious Diseases : IJID : Official Publication of the International Society for Infectious Diseases, vol. 98, 2020, pp. 113-120.
Njuma Libwea J, Gröndahl-Yli-Hannuksela K, Kobela M, et al. Prevalence of pneumococcal nasopharyngeal colonization and serotypes circulating in Cameroonian children after the 13-valent pneumococcal conjugate vaccine introduction. Int J Infect Dis. 2020;98:113-120.
Njuma Libwea, J., Gröndahl-Yli-Hannuksela, K., Kobela, M., Toropainen, M., Nyholm, O., Ndombo, P. K., Koulla-Shiro, S., Nohynek, H., Nuorti, J. P., Vuopio, J., & Palmu, A. A. (2020). Prevalence of pneumococcal nasopharyngeal colonization and serotypes circulating in Cameroonian children after the 13-valent pneumococcal conjugate vaccine introduction. International Journal of Infectious Diseases : IJID : Official Publication of the International Society for Infectious Diseases, 98, 113-120. https://doi.org/10.1016/j.ijid.2020.06.048
Njuma Libwea J, et al. Prevalence of Pneumococcal Nasopharyngeal Colonization and Serotypes Circulating in Cameroonian Children After the 13-valent Pneumococcal Conjugate Vaccine Introduction. Int J Infect Dis. 2020;98:113-120. PubMed PMID: 32562849.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Prevalence of pneumococcal nasopharyngeal colonization and serotypes circulating in Cameroonian children after the 13-valent pneumococcal conjugate vaccine introduction. AU - Njuma Libwea,John, AU - Gröndahl-Yli-Hannuksela,Kirsi, AU - Kobela,Marie, AU - Toropainen,Maija, AU - Nyholm,Outi, AU - Ndombo,Paul Koki, AU - Koulla-Shiro,Sinata, AU - Nohynek,Hanna, AU - Nuorti,J Pekka, AU - Vuopio,Jaana, AU - Palmu,Arto A, Y1 - 2020/06/17/ PY - 2020/04/02/received PY - 2020/06/14/revised PY - 2020/06/15/accepted PY - 2020/6/21/pubmed PY - 2020/10/27/medline PY - 2020/6/21/entrez KW - Cameroon KW - Nasopharyngeal carriage KW - Pneumococcal conjugate vaccines KW - Serotypes KW - Streptococcal pneumoniae SP - 113 EP - 120 JF - International journal of infectious diseases : IJID : official publication of the International Society for Infectious Diseases JO - Int J Infect Dis VL - 98 N2 - 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. SN - 1878-3511 UR - https://www.unboundmedicine.com/medline/citation/32562849/Prevalence_of_pneumococcal_nasopharyngeal_colonization_and_serotypes_circulating_in_Cameroonian_children_after_the_13_valent_pneumococcal_conjugate_vaccine_introduction_ L2 - https://linkinghub.elsevier.com/retrieve/pii/S1201-9712(20)30483-5 DB - PRIME DP - Unbound Medicine ER -