Background: Pneumococcal nasopharyngeal colonization is a prerequisite to developing pneumococcal disease. We investigated the dynamics of pneumococcal colonization in perinatal HIV-unexposed and HIV-exposed children and their mothers and risk factors associated with new serotypes acquisition.
Methods: Two hundred forty-three mother–child pairs (120 HIV-infected, 123 HIV-uninfected mothers) were studied at 4.4, 7.2, 9.4, 12.3 and 16.0 months of the child’s age. Demographic data, nasopharyngeal swabs, as well as oropharyngeal swabs, from mothers were collected for pneumococcal conventional culture and serotyping by the Quellung method.
Results: The rate of new serotype acquisition during the 16 months did not differ between HIV-exposed (49.1%) and HIV-unexposed (52.0%) children, or between HIV-infected (18.9%) and HIV-uninfected (19.5%) mothers. Serotypes included in the 7-valent pneumococcal conjugate vaccine (PCV7) were acquired more often by HIV-infected (10.0%) compared with HIV-uninfected mothers (6.4%; P = 0.03). On multivariate analysis, day-care attendance (adjusted odds ratio [AOR], = 1.80, P = 0.02) and maternal pneumococcal colonization (AOR = 1.54, P = 0.01) were positively associated with pneumococcal acquisition in the child, whereas breast-feeding had a protective effect on PCV7-serotype acquisition in HIV-uninfected children. New acquisition of PCV7 and PCV13 serotypes in the mother was positively associated with colonization in the child (AOR = 2.01, P = 0.006 and AOR = 2.04, P = 0.002, respectively).
Conclusions: There is an association of acquisition of PCV7 and PCV13 serotypes between young children and their mothers. The higher prevalence of PCV7 serotype in HIV-infected mothers suggests that they may be a reservoir for transmission of these serotypes, which could delay indirect effects of PCV in settings with a high HIV burden.
From the *Department of Science and Technology/National Research Foundation: Vaccine Preventable Diseases and †Medical Research Council: Respiratory and Meningeal Pathogens Research Unit, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa; ‡National Institute for Communicable Diseases: a division of National Health Laboratory Service, Centre for Respiratory and Meningites Diseases, Sandringham, South Africa; and §Hubert Department of Global Health, Rollins School of Public Health, and Division of Infectious Diseases, School of Medicine, Emory University, Atlanta, GA.
Accepted for publication 4, 2013.
M.C.N. had financial support from the University of the Witwatersrand. The conduct of the study was funded by a grant from Bill and Melinda Gates—Grand Challenge Program: PneumoCarr project. The authors have no other funding or conflicts of interest to disclose.
The results of this study were presented in-part at the 8th International Symposium on Pneumococci and Pneumococcal Diseases in Brazil, March 11-15 2012. Abstract number: 84
Address for correspondence: Shabir A. Madhi, MD, PhD, National Institute for Communicable Diseases: a division of National Health Laboratory Service, 1 Modderfontein Road, Sandringham, Gauteng; 2131; South Africa. E-mail: email@example.com.