Acquisition of Streptococcus pneumoniae in South African children vaccinated with 7-valent pneumococcal conjugate vaccine at 6, 14 and 40 weeks of age. Issue 5 (29th January 2015)

• Record Type: Journal Article
• Authors: Nunes, Marta C.; Jones, Stephanie A.; Groome, Michelle J.; Kuwanda, Locadiah; Van Niekerk, Nadia; von Gottberg, Anne; de Gouveia, Linda; Adrian, Peter V.; Madhi, Shabir A.
• Is Part Of: Vaccine. Volume 33:Issue 5(2015)
• Page Start: 628
• Page End: 634
• Publication Date: 2015-01-29
• Subjects: Vaccines -- Periodicals; 615.372
• DOI: 10.1016/j.vaccine.2014.12.023
• Languages: English
• ISSNs: 0264-410X

Abstract

<abstract abstract-type="author" id="abs0005"> <title id="sect0005">Abstract</title> <sec> <title id="sect0010">Background</title> <p id="spar0005">Seven-valent pneumococcal conjugate vaccine (PCV7) was introduced into the South African immunization program using 6, 14 and 40 weeks dosing schedule (2 + 1), with no catch-up in older children since April 2009. We investigated pneumococcal colonization acquisition in children who received this schedule and also compared it to historical cohorts of PCV-naïve children (<italic>n</italic> = 123 in 2007) and children who received a 3 + 1 PCV7 schedule (<italic>n</italic> = 124 in 2005/06).</p> </sec> <sec> <title id="sect0015">Methods</title> <p id="spar0010">Two hundred and fifty children aged 6–12 weeks were enrolled from December 2009 to April 2010. Participants had nasopharyngeal swabs collected on eight occasions between enrolment and 2-years of age. Standard methods were undertaken for bacterial culture and <italic>Streptococcus pneumoniae</italic> were serotyped using the Quellung method. Pneumococcal and <italic>Staphylococcus aureus</italic> colonization in the present study was compared to colonization in two historical longitudinal cohorts.</p> </sec> <sec> <title id="sect0020">Results</title> <p id="spar0015"> <italic>S. pneumoniae</italic> was identified in 1081 (61.4%) of 1761 swabs collected in the current cohort. Pneumococcal colonization peaked at 41-weeks of age (76.8%) and decreased to 62.8% by 2-years of age (<italic>p</italic> = 0.002); PCV7-serotype colonization decreased during the same period from 28.6% to 15.6% (<italic>p</italic> = 0.001). Children from the current cohort compared to PCV-naïve children were less likely to be colonized by PCV7-serotypes from 40-weeks to 2-years of age and acquired PCV7-serotypes less frequently. No differences in overall pneumococcal, PCV7-serotype and non-PCV7-serotype colonization or new serotype acquisitions were detected comparing the current cohort to the historical cohort who received the 3 + 1 PCV7 schedule. <italic>Staphylococcus aureus</italic> colonization was similar in all three cohorts.</p> </sec> <sec> <title id="sect0025">Conclusion</title> <p id="spar0020">A 2 + 1 PCV7 schedule implemented in South Africa was temporally associated with reduced risk of vaccine-serotype colonization compared to historically unvaccinated children. Also, vaccine-serotype acquisition rate using the 2 + 1 schedule was similar to that in the 3 + 1 dosing cohort, suggesting that similar indirect protection against pneumococcal disease could be derived from either schedule in South Africa.</p> </sec> </abstract>