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Nasopharyngeal carriage of Streptococcus pneumoniae in Gambian infants: a longitudinal study

Philip C Hill1, Yin Bun Cheung, Abiodun Akisanya

  • 1Bacterial Diseases Programme, MRC Laboratories, Banjul, The Gambia. pandmhill@hotmail.com

Clinical Infectious Diseases : an Official Publication of the Infectious Diseases Society of America
|February 19, 2008
PubMed

Insights

All Gambian infants carried Streptococcus pneumoniae, with carriage duration varying by serotype. This data is crucial for assessing the impact of new pneumococcal conjugate vaccines in Africa.

Area of Science:

  • Microbiology
  • Epidemiology
  • Vaccinology

Background:

  • Nasopharyngeal carriage of Streptococcus pneumoniae (pneumococcus) is a key factor in disease transmission.
  • Understanding carriage dynamics is essential for the effective implementation of pneumococcal conjugate vaccines (PCVs).

Purpose of the Study:

  • To establish baseline data on pneumococcal carriage in Gambian infants prior to the introduction of a restricted valency PCV.
  • To analyze the time to acquisition and duration of carriage for different pneumococcal serotypes.

Main Methods:

  • A cohort of 236 infants in The Gambia was followed for one year.
  • Nasopharyngeal swabs were collected at birth, bi-monthly for six months, and then bi-monthly until one year of age.
  • Time to acquisition and duration of carriage were analyzed based on pneumococcal serotype.

Main Results:

  • All infants acquired Streptococcus pneumoniae carriage during the study period.
  • Sixty-five serotypes were identified, with the top 5 accounting for 51% of isolates.
  • While acquisition rates did not differ significantly between serotypes or vaccine groups, carriage duration varied significantly, with non-vaccine types carried for shorter durations than vaccine types.

Conclusions:

  • This study provides critical baseline data on pneumococcal carriage dynamics in Gambian infants.
  • The findings are vital for evaluating the future impact of pneumococcal conjugate vaccine introduction in The Gambia and other African regions.
  • Understanding serotype-specific carriage duration is important for vaccine effectiveness assessments.
Abstract

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