Rates of Acquisition of Pneumococcal Colonization and Transmission Probabilities, by Serotype, Among Newborn Infants in Kilifi District, Kenya
Open Access
- 20 April 2012
- journal article
- research article
- Published by Oxford University Press (OUP) in Clinical Infectious Diseases
- Vol. 55 (2), 180-188
- https://doi.org/10.1093/cid/cis371
Abstract
Background. Herd protection and serotype replacement disease following introduction of pneumococcal conjugate vaccine (PCV) are attributable to the vaccine's impact on colonization. Prior to vaccine introduction in Kenya, we did an epidemiological study to estimate the rate of pneumococcal acquisition, by serotype, in an uncolonized population. Methods. Nasopharyngeal swab specimens were taken from newborns aged ≤7 days and weekly thereafter for 13 weeks. Parents, and siblings aged Results. Of 1404 infants recruited, 887 were colonized by 3 months of age, with the earliest acquisition detected on the first day of life. The median time to acquisition was 38.5 days. The pneumococcal acquisition rate was 0.0189 acquisitions/day (95% confidence interval, .0177–.0202 acquisitions/day). Serotype-specific acquisition rates varied from 0.00002–0.0025 acquisitions/day among 49 different serotypes. Season, coryza, and exposure to cigarettes, cooking fumes, and other children in the home were each significant risk factors for acquisition. The transmission probability per 30-day duration of contact with a carrier was 0.23 (95% CI, .20–.26). Conclusions. Newborn infants in Kilifi have high rates of nasopharyngeal acquisition of pneumococci. Half of these acquisitions involve serotypes not included in any current vaccine. Several risk factors are modifiable through intervention. Newborns represent a consistent population of pneumococcus-naive individuals in which to estimate the impact of PCV on transmission.Keywords
This publication has 34 references indexed in Scilit:
- Rates of Acquisition and Clearance of Pneumococcal Serotypes in the Nasopharynges of Children in Kilifi District, KenyaThe Journal of Infectious Diseases, 2012
- Estimating Rates of Carriage Acquisition and Clearance and Competitive Ability for Pneumococcal Serotypes in Kenya With a Markov Transition ModelEpidemiology, 2012
- Profile: The Kilifi Health and Demographic Surveillance System (KHDSS)International Journal of Epidemiology, 2012
- Improved Detection of Nasopharyngeal Cocolonization by Multiple Pneumococcal Serotypes by Use of Latex Agglutination or Molecular Serotyping by MicroarrayJournal of Clinical Microbiology, 2011
- Serotype replacement in disease after pneumococcal vaccinationThe Lancet, 2011
- Association of Secondhand Smoke Exposure with Pediatric Invasive Bacterial Disease and Bacterial Carriage: A Systematic Review and Meta-analysisPLoS Medicine, 2010
- Influenza Enhances Susceptibility to Natural Acquisition of and Disease due toStreptococcus pneumoniaein FerretsThe Journal of Infectious Diseases, 2010
- Nasopharyngeal Carriage of Streptococcus pneumoniae in Gambian Children who Participated in a 9-valent Pneumococcal Conjugate Vaccine Trial and in Their Younger SiblingsThe Pediatric Infectious Disease Journal, 2009
- The Descriptive Epidemiology of Streptococcus pneumoniae and Haemophilus influenzae Nasopharyngeal Carriage in Children and Adults in Kilifi District, KenyaThe Pediatric Infectious Disease Journal, 2008
- Invasive Pneumococcal Disease Caused by Nonvaccine Serotypes Among Alaska Native Children With High Levels of 7-Valent Pneumococcal Conjugate Vaccine CoverageJAMA, 2007