Longitudinal study on Streptococcus pneumoniae, Haemophilus influenzae and Staphylococcus aureus nasopharyngeal colonization in HIV-infected and -uninfected infants vaccinated with pneumococcal conjugate vaccine

Abstract

Background: Streptococcus pneumoniae, Haemophilus influenzae and Staphylococcus aureus are all potentially pathogenic, which frequently colonize the nasopharynx (NP) prior to causing disease. We studied bacterial NP-colonization in 321 HIV-infected and 243 HIV-uninfected children vaccinated with 7-valent pneumococcal conjugate vaccine (PCV7) at 6, 10 and 14 weeks of age.

Methods: HIV-uninfected infants included those born to HIV-uninfected (HUU) and HIV-infected women (HEU); HIV-infected children with CD4+ lymphocyte ≥25% were randomized to initiate antiretroviral therapy immediately (ART-Immed) or when clinically indicated (ART-Def). Nasopharyngeal swabs for bacterial culture were taken prior to each PCV7 dose (Visits 1-3) and at 20, 39, 47 and 67 weeks of age (Visits 4-7). Swabs were cultured by standard methods and pneumococcal serotyping done by the Quellung method.

Results: Colonization patterns for pneumococcus, H. influenzae and S. aureus did not differ between HUU and HEU children; and were also generally similar between ART-Def and ART-Immed children. Prevalence of PCV7-serotype colonization was similar between HIV-infected and HIV-uninfected children, however, overall pneumococcal and specifically non-vaccine serotype colonization tended to be lower in HIV-infected children. HIV-infected children also had a 44% lower prevalence of S. aureus colonization at Visit-1 (p=0.010); and H. influenzae colonization was also lower among HIV-infected than HIV-uninfected children at Visit-2, Visit-3, Visit-6 and Visit-7.

Conclusion: Vaccine-serotype colonization is similar in PCV-immunized HIV-infected and HIV-uninfected children. We, however, identified a lower prevalence of overall-pneumococcal and H. influenzae colonization in HIV-infected children post-PCV vaccination, the clinical-relevance of which warrants further study.

Trial registration: ClinicalTrials.gov NCT00099658.

Keywords: Colonization; HIV; HIV exposure; Haemophilus influenzae; Pneumococcal conjugate vaccine; Staphylococcus aureus; Streptococcus pneumoniae.

Conflict of interest statement

Conflict of interest: Receipt of research funding, honoraria and consultancy from Pfizer (SAM). Receipt of research grants, consultancies and honoraria from GSK (SAM, KPK). Receipt of research funding from Pfizer (AvG). Prevenar was donated by Wyeth Vaccines and Pediatrics (now Pfizer).

Copyright © 2015 Elsevier Ltd. All rights reserved.

Figures

Figure 1

Pneumococcal colonization prevalence in HIV-infected and HIV-uninfected infants during the first 18 months of life. * = significant difference (p

Figure 2

Staphylococcus aureus and Haemophilus influenzae colonization prevalence in HIV-infected and HIV-uninfected infants during the first 18 months of life. * = significant difference (p