Mathematical assessment of the impact of cohort vaccination on pneumococcal carriage and serotype replacement

Tufail M. Malik, Jemal Mohammed-Awel, Abba B. Gumel, Elamin H. Elbasha

Research output: Contribution to journalArticlepeer-review

1 Scopus citations


Although pneumococcal vaccines are quite effective in reducing disease burden, factors such as imperfect vaccine efficacy and serotype replacement present an important challenge against realizing direct and herd protection benefits of the vaccines. In this study, a novel mathematical model is designed and used to describe the dynamics of two Streptococcus pneumoniae (SP) serotypes, in response to the introduction of a cohort vaccination program which targets one of the two serotypes. The model is fitted to a pediatric SP carriage prevalence data from Atlanta, GA. The model, which is rigorously analysed to investigate the existence and asymptotic stability properties of the associated equilibria (in addition to exploring conditions for competitive exclusion), is simulated to assess the impact of vaccination under different levels of serotype-specific competition and illustrate the phenomenon of serotype replacement. The calibrated model is used to forecast the carriage prevalence in the pediatric cohort over 30 years.

Original languageEnglish (US)
Pages (from-to)S214-S247
JournalJournal of biological dynamics
Issue numberS1
StatePublished - 2021


  • Streptococcus pneumoniae
  • carriage-free equilibrium
  • co-colonization
  • competitive exclusion
  • pneumococcal carriage
  • serotype replacement

ASJC Scopus subject areas

  • Ecology, Evolution, Behavior and Systematics
  • Ecology


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