PATH’s Center for Vaccine Innovation and Access

Typhoid

Turning a centuries-old disease into a distant memory

Photo: PATH/Rocky Prajapati

Photo: PATH/Rocky Prajapati

Typhoid, also known as enteric fever, is a serious infectious disease caused by the bacteria Salmonella typhi and spread through contaminated food and water. While largely eliminated from industrialized countries, typhoid continues to be a substantial public health issue threatening children and poor populations in much of Asia and sub-Saharan Africa. It is estimated to cause 12 to 21 million cases and almost 150,000 deaths each year, with young children and adolescents aged 2 to 15 years disproportionately impacted.

Symptoms of typhoid include fever, fatigue, headache, abdominal pain, and diarrhea or constipation. These symptoms are often mistaken for other diseases such as malaria, pneumonia, dengue fever, influenza, or other febrile illnesses, leading to frequent misdiagnoses. If left untreated, typhoid can cause serious short- and long-term complications, such as intestinal perforation, encephalitis, pneumonia, delirium, and severe dehydration, which can be life-threatening. Typhoid can be effectively treated with antibiotics, though the rate of cases resistant to available antibiotics is increasing. Two vaccines are currently available to prevent typhoid and are frequently used during outbreaks, however neither can be used in children less than two years of age—thus excluding an age group with a large burden of disease and preventing inclusion in routine childhood vaccination programs.

An integrated approach to typhoid prevention

Vaccines—along with improvements in water, sanitation, and hygiene (WASH) programs—are the best ways to prevent typhoid. Newer typhoid conjugate vaccines (TCVs) have the potential to provide longer-lasting protection than existing vaccines and could be used in routine immunization programs for children less than two years old, protecting a vulnerable cohort. With the increasing threat of antibiotic resistance and the significant burden of typhoid among hard-to-reach populations where WASH infrastructure is difficult to implement, the role of vaccines in conjunction with WASH interventions is critical for high-risk and marginalized areas. Due to the substantial and detrimental impact of typhoid, we are committed to ensuring that typhoid prevention and control is a global health priority.

Accelerating the introduction of typhoid conjugate vaccines

As a core partner of the Typhoid Vaccine Acceleration Consortium (TyVAC), we work to accelerate the introduction of TCVs in low- and middle-income countries and facilitate access to TCVs in the most at-risk communities as part of an integrated solution to combat typhoid. We employ a multidisciplinary strategy to typhoid prevention and control, working at the global, regional, and national levels.

Global and national immunization decision makers need accurate, up-to-date information to make evidence-based decisions about new vaccine introductions. We assess and disseminate the latest evidence and we work to generate new evidence where knowledge gaps exist, particularly for key questions of disease burden, antimicrobial resistance, cost effectiveness, and the health impact of TCVs. Globally, we work closely with organizations like the World Health Organization (WHO) and Gavi, the Vaccine Alliance to ensure that sufficient data are available to inform global typhoid guidelines. Locally, we provide the latest evidence and support to interested countries in program preparation.

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