academic journalism

Serotype Replacement and Nasopharyngeal Carriage Due to the Introduction of New Pneumococcal Conjugate Vaccine to National Routine Immunization


avatar Manoochehr Karami 1 , * , avatar Mohammad Yousef Alikhani 2

1 Research Center for Health Sciences and Department of Epidemiology, School of Public Health, Hamadan University of Medical Sciences, Hamadan, IR Iran

2 Brucellosis Research Center, Hamadan University of Medical Sciences, Hamadan, IR Iran

How to Cite: Karami M, Alikhani M Y. Serotype Replacement and Nasopharyngeal Carriage Due to the Introduction of New Pneumococcal Conjugate Vaccine to National Routine Immunization. Jundishapur J Microbiol. 2015;8(10):e24807.
doi: 10.5812/jjm.24807.


Jundishapur Journal of Microbiology: 8 (10); e24807
Published Online: October 17, 2015
Article Type: Editorial
Received: October 24, 2014
Revised: March 4, 2015
Accepted: May 11, 2015

Streptococcus pneumonia is still considered a main challenge towards achieving Millennium Development Goal 4 (MDG4) with more than 500000 deaths worldwide among children under 5 years in 2008 (1). Because of the considerable burden of S. pneumonia related diseases such as meningitis, pneumonia, and sepsis, the world health organization (WHO) recommended introduction of pneumococcal conjugate vaccine (PCV) to national routine immunization. Like many countries, Iran is currently preparing to introduce PCV. Epidemiological pattern of S. pneumonia after PCV vaccine implementation will be changed and the prevalence of both nasopharyngeal carriage and transmission will be reduced. In addition, the epidemiology of S. pneumonia is affected among non-targeted vaccination population because of indirect effect of vaccination (1).

Prevalence of nasopharyngeal carriage is estimated as 85% in developing countries (2). According to Davis et al. findings, nasopharyngeal carriage following PCV introduction among 14 countries were detected in population groups not targeted for immunization against S. pneumonia (3). Moreover, some studies (4, 5) found that the distribution of vaccine and non-vaccine serotypes has changed after PCV introduction. This epidemiological transition leads to increase in the incidence of those serotypes, which are not included in the PCV vaccine. There are limited or unreliable data on nasopharyngeal carriage and serotype replacement of pneumococcus in Iran. In conclusion, interested researchers in the field of microbiology and epidemiology are advised to conduct repeated surveys or monitor surveillance data to draw the profile of S. pneumonia related diseases at local and national levels.


  • 1.

    Measuring impact of Streptococcus pneumoniae and Haemophilus influenzae type b conjugate vaccination. 2012;

  • 2.

    WHO Publication. . Pneumococcal vaccines WHO position paper - 2012 - recommendations Vaccine . 2012; 30 (32) : 4717 -8 [PubMed]

  • 3.

    Davis SM, Deloria-Knoll M, Kassa HT, O'Brien KL. Impact of pneumococcal conjugate vaccines on nasopharyngeal carriage and invasive disease among unvaccinated people: review of evidence on indirect effects. Vaccine. 2013; 32 (1) : 133 -45 [DOI][PubMed]

  • 4.

    Pilishvili T, Lexau C, Farley MM, Hadler J, Harrison LH, Bennett NM, et al. Sustained reductions in invasive pneumococcal disease in the era of conjugate vaccine. J Infect Dis. 2010; 201 (1) : 32 -41 [DOI][PubMed]

  • 5.

    Lehmann D, Willis J, Moore HC, Giele C, Murphy D, Keil AD, et al. The changing epidemiology of invasive pneumococcal disease in aboriginal and non-aboriginal western Australians from 1997 through 2007 and emergence of nonvaccine serotypes. Clin Infect Dis. 2010; 50 (11) : 1477 -86 [DOI][PubMed]

Copyright © 2015, Ahvaz Jundishapur University of Medical Sciences. This is an open-access article distributed under the terms of the Creative Commons Attribution-NonCommercial 4.0 International License ( which permits copy and redistribute the material just in noncommercial usages, provided the original work is properly cited.