Typhoid

Typhoid fever is a bacterial disease spread through food or drink that is contaminated with the waste of an infected person. Symptoms include fever, headache, constipation, and malaise. It is difficult to diagnose due to the lack of distinctive symptoms. There are 12-21 million cases of typhoid fever and up to 223,000 deaths annually, with the highest burden in South Asia.

IVI’s Typhoid Program encompasses an array of activities across the vaccine value chain, including the development of the typhoid conjugate vaccine (Vi-DT), disease surveillance for typhoid fever, and the deployment of this and other typhoid conjugate vaccines (TCVs) accompanied by effectiveness studies in Africa, Asia, and Pacific islands.

Clinical development

Developing a new-generation typhoid conjugate vaccine

IVI developed Vi-DT, a new-generation typhoid conjugate vaccine designed to provide strong immunogenicity in young children. The technology was successfully transferred to Korea-based SK bioscience in 2013 and to Indonesia’s Bio Farma in 2014.

In 2024, SK bioscience’s SKYTyphoid™ achieved World Health Organization prequalification following successful Phase III trials in the Philippines and Nepal. Prequalification enables UN organizations to procure the vaccine, increasing the global supply at a time of urgent demand. Bio Farma’s Bio-TCV® was approved in Indonesia in 2023, with plans to seek World Health Organization prequalification.

IVI is also working on developing combination vaccines using the TCV, including the one for invasive Non-Typhoidal Salmonellae (iNTS).

Epidemiology and capacity-building

Surveillance for TCV Impact Assessment in Africa

From 2010 to 2014, IVI conducted the Typhoid Surveillance in Africa Program (TSAP) which included ten sub-Saharan African countries, providing the foundational data on the burden of typhoid fever across the region.

In 2015, IVI launched a multicountry study called the Severe Typhoid in Africa (SETA) project (2015-2019) to assess the burden of typhoid fever in six sub-Saharan African countries with high incidence of typhoid fever. The study collected data on disease incidence, severity, sequelae, and economic impact, as well as on invasive salmonellosis.

The study transitioned to SETA Plus (2020-2023) and has evolved into the Surveillance for TCV Impact Assessment in Africa (STIA) project, currently focusing on Burkina Faso, Democratic Republic of the Congo, Ghana, Madagascar, and Nigeria.

Typhoid Conjugate Vaccine Introduction in Africa

Launched in 2019 alongside the Severe Typhoid in Africa program, the Typhoid Conjugate Vaccine Introduction in Africa (THECA) project addresses key research questions about rolling out typhoid conjugate vaccines in Africa. The project includes clinical trials, mass vaccination campaigns, and advocacy across four countries:

  • Ghana: Typhoid Vaccine Effectiveness Study in Ghana (TyVEGHA) is a cluster-randomized Phase IV controlled trial assessing the impact of the Vi-Polysaccharide conjugate vaccine in preventing typhoid infection in Asante Akim, Ghana. The trial involved the vaccination of about 20,000 children aged 9 months to under 16 years with the Vi-TT vaccine. The vaccination campaign completed in 2022.
  • Democratic Republic of the Congo: Typhoid Vaccine Effectiveness Study in Democratic Republic of the Congo (TyVECO) included a mass vaccination with Typbar-TCV® in children aged 6 to 16 years. More than 44,300 children were vaccinated. A three-year surveillance of typhoid fever and census updates are underway to assess the vaccine effectiveness.
  • Madagascar: The response has included a mass vaccination and evaluation of TYPHIBEV® effectiveness.
  • Burkina Faso: In January 2025, Burkina Faso became the first Francophone African country to introduce TCVs into its routine immunization program at 9 months of age. This milestone followed a successful vaccination campaign that month that targeted around 10.2 million children aged 9 months to 14 years in all the country’s 70 health districts. The TCV introduction was supported by evidence from TSAP, SETA, and SETA Plus that played a crucial role in informing decision-making through THECA.
Launch of the mass vaccination in Kisantu, Democratic Republic of the Congo.
Launch of the mass vaccination campaign by the Minister of Health of Burkina Faso in January 2025.

Typhoid in Fiji – Vaccination towards Elimination

In partnership with the Fijian Expanded Program on Immunization, the Typhoid in Fiji – Vaccination towards Elimination (Ty-FIVE) project aims to vaccinate the population of Vanua Levu to protect the island from typhoid fever. The project also assesses the preventive impact and feasibility of a single-dose regimen of the Vi-TT typhoid conjugate vaccine.

In 2023, about 70,000 people in Fiji’s northern division were vaccinated as part of this proof-of-concept initiative. Since April 2024, a birth-cohort vaccination program has provided vaccines to babies and their parents or guardians. Vaccinations also expanded to other regions and to the national military.

By November 2024, 19 typhoid cases were confirmed post-vaccination, down from 55 the previous year. Notably, none had received the TCV. This reduction highlights the campaign’s success, with results shared with local decision-makers and the World Health Organization.


“A vaccination campaign requires a lot of manpower and resources, not only from the health personnel but from the communities as well. I’m hopeful and excited that this effort will be an answer to typhoid endemicity in Fiji.”

Dr. Alumita Vuakanisakea, Project Lead, Ty-FIVE Project

A team of public health workers set up a vaccination site in the Daroko settlement of Vunivesi in Cakaudrove during Fiji's Northern Division’s typhoid conjugate vaccine campaign. Credit: IVI/Navneel Kumar

Typhoid Silent Contamination Surveillance

The Typhoid Silent Contamination Surveillance (Ty-SICS) project in Fiji assesses the environmental prevalence of Salmonella Typhi before and after the Ty-FIVE vaccination campaign in parallel with symptomatic typhoid surveillance. Monthly samples are collected from 35 surface water sampling sites across the island of Vanua Levu, the main island of the Northern Division, to detect the presence of S. Typhi and fecal contamination using the polymerase chain reaction (PCR) technique.

Preliminary data analysis and mapping of clinical and environmental Salmonella cases, alongside regional vaccination coverage, revealed a reduction in both clinical cases and environmental positivity following the vaccination campaign.

Typhoid Conjugate Vaccine Introduction in Madagascar

The Typhoid Conjugate Vaccine Introduction in Madagascar (TyMA) project aims to curb the spread of typhoid fever in the country by vaccinating at-risk groups and supporting the development of a national control plan. The vaccine effectiveness study uses the TYPHIBEV® vaccine and includes a geographic information system-supported census, vaccination, and surveillance.

By November 2024, over 36,500 people, including 33,000 children, were vaccinated. The study includes an age-stratified immunogenicity assessment and a sub-study on vaccine impact on antimicrobial resistance. Both passive and active surveillance are ongoing, identifying typhoid-positive cases and conducting monthly household visits to better estimate the true burden of Salmonella Typhi.

Mozambique Typhoid Fever Surveillance

The Mozambique Typhoid Fever Surveillance (MOTiF) project evaluates the burden of typhoid fever in the country, aiming to provide decision-makers with evidence to support the introduction of typhoid conjugate vaccines. Some surveillance activities concluded in 2024, and other surveillance continues in 2025.

Typhoid surveillance in Peru, Brazil, and Ethiopia

In 2024, IVI launched three projects to estimate the seroincidence of Salmonella Typhi and Salmonella Paratyphi A infections in Peru, Brazil, and Ethiopia.

  • Peruvian Investigation of Pathogenic Enterobacterales (PIPE): Peru has reported diverse Salmonella infections but lacks systematic surveillance. The first phase includes a serosurvey in five high-risk regions (Arequipa, Lima, Loreto, Tumbes, and Ucayali), with 550 participants enrolled by mid-November 2024. The next phase will implement blood culture surveillance to estimate the incidence of typhoid, paratyphoid, invasive non-typhoidal Salmonella, and other pathogenic Enterobacterales, and assess antimicrobial resistance.
  • Enteric Fever Surveillance in Indigenous Populations in Brazil (EFSIB): Typhoid fever has not been systematically studied in Latin America. IVI is conducting a population-based serosurvey in Maués, Brazil, alongside the PIPE study, with data collection set for 2025.
  • Enteric Fever Serosurveillance in Ethiopia (EFEp): Ethiopia reports fewer confirmed Salmonella Typhi cases than other African countries. This study will assess the burden of typhoid fever in urban and rural areas of Asoso and Welkite, with data collection starting in 2024.

Page updated: March 2025