S.  Mushayabasa, 
    Impact of Vaccines on Controlling Typhoid Fever in Kassena-Nankana District of Upper East Region of Ghana: Insights from a Mathematical Model,
    Journal of Modern Mathematics and Statistics,
    Volume 5,Issue 2,
    2011,
    Pages 54-59,
    ISSN 1994-5388,
    jmmstat.2011.54.59,
    (https://makhillpublications.co/view-article.php?doi=jmmstat.2011.54.59)
    Abstract: Vaccination is an important prevention and control measure for the spread of typhoid fever. In this study, we develop a simple mathematical model to explore the impact of vaccination on the transmission dynamics of typhoid fever in Kassena-Nankana district of Upper East region of Ghana. Analytical results of the model show that the quantities R<SUB>v</SUB> and R<SUB>0</SUB> which represent the vaccine-induced reproduction number and the no vaccine induced reproduction number, respectively provide threshold conditions that determine the prevalence of typhoid fever in a community. These threshold conditions can be used to gain important insights into the impact of vaccination on controlling typhoid fever. Numerical results have been provided to illustrate the analytical findings.
    Keywords: Salmonella paratyphi;typhoid fever;vaccines;reproductive number;Zimbabwe;stability