Typhoid: Study confirms Vi-DT conjugate vaccine is safe and immunogenic in children 6-23 months

September 17, 2020

September 17, 2020 - SEOUL, South Korea - A new study conducted by IVI in collaboration with SK bioscience shows that single-dose and two-dose regimens of Vi-DT typhoid conjugate vaccine (TCV) are safe and immunogenic in children 6-23 months of age, a group with high rates of typhoid fever in resource-limited settings. The findings from this study newly published online in The Lancet's EClinicalMedicine describe the successful completion and analysis of a Phase II clinical trial of Vi-DT six months after vaccination.

The World Health Organization (WHO) recommends TCVs for use in endemic settings with Gavi, the Vaccine Alliance providing the vaccines to eligible countries. However, with only one TCV pre-qualified by the WHO, demand currently exceeds supply. This study is a critical step toward gaining licensure and WHO-prequalification of an additional TCV to increase the global stockpile.

"Our findings show that a single dose of conjugated Vi-DT vaccine is safe and provides anti-Vi seroconversion rates similar to the two-dose regimen in children between 6 months and 2 years of age," said Dr. Birkneh Tilahun Tadesse, a Research Scientist at the International Vaccine Institute (IVI), which conducted the study at the Research Institute for Tropical Medicine in Manila, the Philippines.

"This is an important advance considering the significant burden of disease in infants and young children, and our goal remains developing a safe, single-dose vaccine with long-lasting immunogenicity to protect more children against typhoid fever," said Dr. Sushant Sahastrabuddhe, Director of the Typhoid Program at IVI.

Increasing global supply of typhoid conjugate vaccines

Vi-DT was developed at IVI and its technology was transferred in 2013 to SK bioscience in South Korea for manufacturing and commercialization. A Phase I safety trial of Vi-DT was first conducted in the Philippines with participants 2-45 years of age and showed that the vaccine was safe and immunogenic four weeks after first dose. Following the successful completion of a Phase II trial with infants under 2 years, large-scale Phase III studies with a single-dose of Vi-DT have started in the Philippines and Nepal in 2020.

The WHO recommends programmatic use of typhoid vaccines to prevent and control typhoid fever with preference for TCVs for their longer-lasting protection, fewer doses, and suitability for children under 2. (1) For treatment, antibiotics are currently the frontline intervention for typhoid fever, but drug-resistant typhoid has emerged across Asia and Africa, highlighting the need for sufficient supply of TCV and sustainable vaccination programs.
-end-
About typhoid

Typhoid fever is an invasive water-borne bacterial infection caused by Salmonella enterica serovar Typhi (S. Typhi) presenting with mild to severe symptoms and even resulting in death. Typhoid is most often contracted through ingestion of food or drink contaminated by bacteria shed by infected people. It is usually characterized by fever, headache, constipation, and malaise, though diagnosis can be difficult due to symptoms common to other febrile illnesses. Figures for burden of disease vary due to this difficulty, however the World Health Organization estimates that 128,000-161,000 people die every year from typhoid fever with 11-21 million annual cases. (2) Typhoid surveillance studies report that a quarter to more than half of all invasive cases are found in children under 5. (3)

About the International Vaccine Institute (IVI)

The International Vaccine Institute (IVI) is a nonprofit inter-governmental organization established in 1997 at the initiative of the United Nations Development Programme (UNDP). Headquartered in Seoul, South Korea, IVI was the first international organization hosted by Korea. IVI has 36 signatory countries and the World Health Organization (WHO) on its treaty, including Korea, Sweden, India, and Finland as state funders.

Our mandate is to make vaccines available and accessible for the world's most vulnerable people. We focus on infectious diseases of global health importance such as cholera, typhoid, shigella, salmonella, schistosomiasis, chikungunya, group A strep, Hepatitis A, HPV, TB, HIV, MERS, COVID-19, as well as antimicrobial resistance. For more information, please visit https://www.ivi.int

CONTACT

Aerie Em, Global Communications & Media Specialist
+82 2 881 1386 | aerie.em@ivi.int

International Vaccine Institute

Related Vaccines Articles from Brightsurf:

Comprehensive safety testing of COVID-19 vaccines based on experience with prior vaccines
'The urgent need for COVID-19 vaccines must be balanced with the imperative of ensuring safety and public confidence in vaccines by following the established clinical safety testing protocols throughout vaccine development, including both pre- and post-deployment,' write David M.

Safety of HPV vaccines in males
A new analysis published in the British Journal of Clinical Pharmacology shows that HPV vaccines are safe and well tolerated in the male population, and the side effects that may occur after immunization are similar in both sexes.

Model could improve design of vaccines, immunotherapies
Researchers have discovered a general property for understanding how immune cell receptors sense and respond to microbial signals, which could lead to more effective vaccines for both existing and novel viruses.

Better vaccines are in our blood
Red blood cells don't just shuttle oxygen from our lungs to our organs: they also help the body fight off infections by capturing pathogens in the blood and presenting them to immune cells in the spleen.

Challenges in evaluating SARS-CoV-2 vaccines
With more than 140 SARS-CoV-2 vaccines in development, the race is on for a successful candidate to help prevent COVID-19.

Designing vaccines from artificial proteins
EPFL scientists have developed a new computational approach to create artificial proteins, which showed promising results in vivo as functional vaccines.

Misinformation on vaccines readily available online
Parents researching childhood vaccinations online are likely to encounter significant levels of negative information, researchers at the University of Otago, Wellington, have found.

Battle with the cancer: New avenues from childhood vaccines
A new research from the University of Helsinki showed for the first time how the pre-immunization acquired through common childhood vaccines can be used to enhance therapeutic cancer treatment.

Personalized cancer vaccines
The only therapeutic cancer vaccine available on the market has so far showed very limited efficacy in clinical trials.

Doubts raised about effectiveness of HPV vaccines
A new analysis of the clinical trials of HPV vaccines to prevent cervical cancer raises doubts about the vaccines' effectiveness.

Read More: Vaccines News and Vaccines Current Events
Brightsurf.com is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to Amazon.com.