A recent publication in PLoS Neglected Tropical Diseases, “Predicting the Impact of Vaccination on the Transmission Dynamics of Typhoid in South Asia: A Mathematical Modeling Study,” by Pitzer et al. highlights the benefits of typhoid vaccination programs in infants and school-aged children. The study — authored by Coalition against Typhoid (CaT) affiliates and members — models the efficacy of the three typhoid vaccines, the Ty21a live oral vaccine, the Vi-polysaccharide (ViPS) vaccine, and the Vi-conjugate (ViCV) vaccine, under different vaccination campaign strategies using data from Vellore, India.
Mathematical models of typhoid vaccines such as this one can promote country decision-making and allow policymakers in endemic areas to better design appropriate vaccination policies – including typhoid immunization programs and plans, and can promote country decision-making.
Of particular note, the recent study suggests that typhoid vaccination can offer significant protection to susceptible, or non-immune, individuals from the disease, particularly when population vaccination rates are at or above 40-50%. Additionally, while only the newest ViCV vaccine is safe for children under 2 years, the research suggests a significant benefit could be obtained from vaccinating infants. Overall, by demonstrating the expected effects of different typhoid vaccination strategies in the long-term, successful mathematical models of typhoid vaccines will allow policymakers to make smarter and more informed decisions.
As part of a broader and integrated effort to control Typhoid Fever, the Coalition against Typhoid is expediting and sustaining rational, evidence-based decisions at the global, regional and national levels regarding the use of typhoid vaccines. CaT works to ensure global typhoid immunization policies are available and disseminated at the regional and national levels, and promote an approach to the control of typhoid that is integrated with other cost-effective public health interventions and strategies.
The founding objective of the Coalition against Typhoid was to ‘do something about typhoid, now.’ While there is much work still to be done, the CaT Secretariat is proud of the research being done by individual CaT members and CaT member organizations to do something about typhoid now.
Photo courtesy of ©Sabin Vaccine Institute/Esther Havens