A single dose of the Typhoid Conjugate Vaccine Typbar TCV® provides long-lasting effectiveness in preventing typhoid in children aged 9 months to 12 years, according to a new study conducted by researchers at the Center for Vaccine Development and Global Health (CVD) at the University of Maryland School of Medicine (UMSOM). The study was carried out in partnership with clinical research program of the Malawi-Liverpool Wellcome Trust (MLW).
Results of the clinical phase 3 study were published today in The Lancet.
The research team recruited over 28,000 healthy children in Malawi and randomly assigned about half of the group to receive the TCV vaccine and the other half an A group meningococcal capsule conjugate (MenA) control vaccine. During the over four-year follow-up period, 24 children in the TCV group and 110 in the MenA group developed typhoid, confirmed by blood cultures. This resulted in an efficacy of 78.3 percent in the TCV group, with one typhoid case prevented for every 163 vaccinated children. TCV was effective in all age groups and remained strong throughout the study period, which ended in 2022, with effectiveness only decreasing by 1.3 percent per year.
Typhoid causes more than 9 million illnesses and at least 110,000 deaths worldwide every year, especially in sub-Saharan Africa and Southeast Asia. It is a contagious bacterial infection caused by consuming contaminated food or beverages. Symptoms include nausea, fever, and abdominal pain, which can be fatal if left untreated.
„These results have significant implications for identifying the contribution of TCVs to controlling and potentially eliminating typhoid in endemic areas,“ wrote the authors of a study published alongside in The Lancet.
In May 2023, the Malawian government launched a nationwide introduction of TCV in children under 15 years old. In the future, all children in Malawi will receive TCV as part of routine immunization at nine months of age.
The newly published study confirms the long-lasting impact of a single TCV injection, even in the youngest children, and provides hope for preventing typhoid in the most vulnerable children. We could not have had a better partner in this endeavor than MLW, whose longstanding excellence in typhoid research and strong surveillance infrastructure made this study possible,“ said Kathleen Neuzil, MD, MPH, CVD Director, Myron M. Levine, MD, DTPH, Professor of Vaccinology, UMSOM, and co-author of the current study.
Kathleen Neuzil, MD, MPH, CVD Director, Myron M. Levine, MD, DTPH, Professor of Vaccinology, UMSOM, and co-author of the current study
„The outstanding track record of the CVD in generating data to expedite public health decision-making continues with this groundbreaking study,“ said UMSOM Dean Mark T. Gladwin, MD, Vice President for Medical Affairs at the University of Maryland, Baltimore, and John Z. and Akiko K. Bowers Distinguished Professor. „The research could not have come at a more critical time as Malawi and other African countries grapple with climate change, extreme weather events, and increasing urbanization patterns likely contributing to an increase in gastrointestinal diseases, including typhoid.“
TyVAC is funded by the Bill & Melinda Gates Foundation. Typbar TCV® is licensed by Bharat Biotech International Limited, Hyderabad, India.
University of Maryland School of Medicine
Patel, PD, et al. (2024) Effectiveness of the Typhoid Conjugate Vaccine: Final Analysis of a 4-Year, Randomized, Controlled Phase-3 Study in Malawian Children. The Lancet. doi.org/10.1016/S0140-6736(23)02031-7.