Tag: Malawi

Categories : Paediatrics VaccinesTags :

Single Dose Typhoid Conjugate Vaccine (TCV) Provides Lasting Efficacy in Children

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Healthy children in Malawi participating in study to test efficacy of typhoid conjugate vaccine. Credit: TyVAC/Madalitso Mvula

A single dose of the typhoid conjugate vaccine, Typbar TCV®, provides lasting efficacy in preventing typhoid fever in children ages 9 months to 12 years old, according to a new phase 3 clinical study published in The Lancet.

The study conducted by researchers at University of Maryland School of Medicine’s (UMSOM) Center for Vaccine Development and Global Health (CVD) and led by in-country partners at the Malawi-Liverpool Wellcome Trust (MLW) Clinical Research Programme.

The research team enrolled more than 28 000 healthy children in Malawi and randomly assigned about half the group to receive the TCV and the other half to receive a meningococcal capsular group A conjugate (MenA) control vaccine. During the more than four years of follow-up, 24 children in the TCV group and 110 in the MenA group developed typhoid fever, which was confirmed via blood culture. That resulted in an efficacy of 78.3% in the TCV group, with one case of typhoid prevented for every 163 children vaccinated. TCV was effective in all age groups and over the study period – which ended in 2022 – vaccine efficacy remained strong, decreasing by only 1.3% per year.

Typhoid fever causes more than 9 million illnesses and at least 110,000 deaths worldwide every year, mostly in sub-Saharan Africa and southeast Asia. It is a contagious bacterial infection that occurs from consuming contaminated food or beverages. Symptoms include nausea, fever, and abdominal pain that, if left untreated, can be deadly.

“These findings have significant implications for identification of the contribution of TCVs in the control and potential elimination of typhoid fever in endemic settings,” wrote the authors of a commentary published in The Lancet alongside the study.

In May 2023, the Malawi government launched a national rollout of the TCV in children under 15 years. Going forward, all children in Malawi will receive TCV at 9 months of age as part of the routine immunisation schedule.

“The newly published study supports the long-lasting impacts of a single shot of TCV, even in the youngest children, and offers hope of preventing typhoid in the most vulnerable children,” said Kathleen Neuzil, MD, MPH, CVD Director, the Myron M. Levine, MD, DTPH, Professor in Vaccinology at UMSOM and coauthor of the current study.  “We could not have had a better partner in this endeavor than MLW, whose long-standing excellence in typhoid research and strong surveillance infrastructure made this study possible.”

“The CVD’s outstanding record of generating data to accelerate public health decisions continues with this landmark study,” said UMSOM Dean Mark T. Gladwin, MD, Vice President for Medical Affairs, University of Maryland, Baltimore, and the John Z. and Akiko K. Bowers Distinguished Professor. “The research could not come at a more critical time when Malawi and other African countries are struggling with climate change, extreme weather events and increased urbanisation patterns, which are likely to contribute to increases in enteric diseases, including typhoid.”

Source: University of Maryland

Categories : VaccinesTags :

Typhoid Vaccine Safe for Children in Sub-Saharan Africa

On By ModernMedia
Source: Pixabay CC0

A typhoid vaccine has proven to be safe and effective for children, which raises hope of fighting the disease in Sub-Saharan Africa, according to a new study conducted in Malawi.

There are more than 1.2 million typhoid cases and 18 703 deaths per year in the region, the researchers wrote. The World Health Organization (WHO) recommended the typhoid conjugate vaccine in 2018 for use in countries where the disease is endemic.

Clinical trials in Malawi showed that a single dose of typhoid conjugate vaccine (the only one licensed for children as young as six months) prevented typhoid in roughly 84% of 14 069 children aged 9 months to 12 years.

“It is a great result for Malawi and for Africa,” says study co-author Melita Gordon, professor of clinical infection, microbiology and immunology at the University of Liverpool and the Malawi-Liverpool-Wellcome Trust Clinical Research Programme.

“We were the only site chosen for the trial on the continent. The other sites were in Nepal and Bangladesh and the results were completely consistent across the three sites.”

Typhoid is endemic in Malawi, which records 400 to 500 cases per 100 000 every year, according to Queen Dube, chief of health services at Malawi’s Ministry of Health.

While typhoid is treatable, it can impair physical and cognitive development in children, affect school attendance and performance, limit productivity and reduce earning potential.

“The existing vaccine could not be used in very young children. In addition, the first line antibiotics have been found to be ineffective against multi-drug resistant strains,” Prof Gordon said. “With this vaccine, we can now expect a reduced typhoid burden.”

After 18 to 24 months of surveillance, the vaccine was found to be safe, with no serious adverse effects on children. It also worked equally well on pre-school aged children.

Prof Gordon explains that the study encountered challenges such as a few children moving out of the research sites within the study period, and COVID-19 forced them to suspend the study for two months.

“However, we eventually managed a good retention rate due to regular text messaging to parents and the hard work of health surveillance assistants in mobilisation activities,” she added.

The efficacy data of the typhoid conjugate vaccine is the first in Africa, according to Gordon, who hopes that other African countries will follow Malawi’s example in planning to roll out the vaccine.

Source: SciDev.Net