A new study, published in the New England Journal of Medicine, finds a single dose of typhoid conjugate vaccine (TCV) — the only typhoid vaccine licensed for children as young as 6 months — is safe and 84 percent effective in protecting against typhoid in Blantyre, Malawi. These are the first efficacy results from Africa and part of a five-year, multi-country project to accelerate introduction of TCV.
The findings are critical as typhoid is an increasing public health threat across sub-Saharan Africa due to the emergence and spread of multi-drug resistant strains, which are now common in Malawi. An estimated 1.2 million typhoid cases and 19,000 deaths occur each year in sub-Saharan Africa, which includes Malawi. The vast majority of these infections occur in school-age and preschool children.
The study is being conducted through a partnership between the University of Maryland School of Medicine’s (UMSOM) Center for Vaccine Development and Global Health (CVD), the Malawi-Liverpool-Wellcome Trust (MLW), and Blantyre Malaria Project (BMP) in Blantyre, Malawi.
The work is part of the Typhoid Vaccine Acceleration Consortium (TyVAC) — a larger effort led by CVD, the Oxford Vaccine Group at the University of Oxford, and PATH. TyVAC aims to accelerate the introduction of TCV as part of an integrated approach to reduce the burden of typhoid in countries eligible for support from Gavi, the Vaccine Alliance.
In 2017, the World Health Organization (WHO) recommended TCV for children 6 months of age and older in typhoid endemic settings.
The new study found that the vaccine prevented typhoid in Malawi — where the incidence of typhoid is high. This helps to pave the way for additional countries to introduce TCV, making it available to all children.
“Our only real option to controlling these new resistant strains of typhoid in a timely way is through the vaccine,” said Professor Melita Gordon, University of Liverpool, MLW, and principal investigator for the Malawi study. “The TCV efficacy data are the first from Africa and offer great promise for the control of this deadly disease across the continent.”
The analysis included more than 28,000 children 9 months to 12 years in Blantyre, Malawi — half received TCV and half received the control, group-A meningococcal (MenA) vaccine. Blood tests performed on children with febrile illness occurring at least two weeks after receiving a study vaccine confirmed typhoid in 10 children in the TCV group and 61 who received MenA. TCV was effective in all age groups, including children under age 5.
Typhoid is a bacterial infection caused by Salmonella enterica serovar Typhi and is a serious threat in many low- and middle-income countries. While typhoid is treatable, the effects can go beyond illness and death. Typhoid can impair physical and cognitive development in children, affect school attendance and performance, limit productivity, and reduce earning potential.
“TCVs have the potential to protect millions of children disproportionately impacted by typhoid. We hope these much-needed data catalyze additional countries to introduce this lifesaving vaccine,” said Kathleen Neuzil, MD, MPH, the Myron M. Levine, MD, DTPH, Professor in Vaccinology at UMSOM. Neuzil is also the director of CVD and principal investigator for TyVAC.
Prevention of typhoid — with vaccines — is critical amid rising antimicrobial resistance. The TyVAC study in Africa helps inform a country’s decision to introduce TCV into their national childhood immunization program to combat the growing threat of antimicrobial resistance occurring globally.
“These findings highlight the burden of typhoid illness and the remarkable impact of a single dose of TCV in improving the health of children in low- and middle-income countries,” said E. Albert Reece, MD, PhD, MBA, executive vice president for medical affairs, University of Maryland, Baltimore, and the John Z. and Akiko K. Bowers Distinguished Professor and dean, UMSOM. “CVD has again harnessed the power of partnership to address the globe’s most pressing problems.”
TyVAC is funded by the Bill & Melinda Gates Foundation. Typbar TCV® is licensed by Bharat Biotech International Limited, Hyderabad, India.
About the Center for Vaccine Development and Global Health at the University of Maryland School of Medicine
For over 40 years, researchers in the Center for Vaccine Development and Global Health (CVD) have worked domestically and internationally to develop, test, and deploy vaccines to aid the world’s underserved populations. CVD is an academic enterprise engaged in the full range of infectious disease intervention from basic laboratory research through vaccine development, pre-clinical and clinical evaluation, large-scale pre-licensure field studies, and post-licensure assessments. CVD has created and tested vaccines against cholera, typhoid fever, paratyphoid fever, non-typhoidal Salmonella disease, shigellosis (bacillary dysentery), Escherichia coli diarrhea, nosocomial pathogens, tularemia, influenza, coronaviruses, malaria, and other infectious diseases. CVD’s research covers the broader goal of improving global health by conducting innovative, leading research in Baltimore and around the world. Our researchers are developing new and improved ways to diagnose, prevent, treat, control, and eliminate diseases of global impact, including COVID-19. In addition, CVD’s work focuses on the ever-growing challenge of antimicrobial resistance.