EDCTP portfolio: Neglected infectious diseases
index
The THECA study will provide important evidence on the impact of typhoid fever vaccination in Africa.
Making the case for typhoid fever vaccination
Typhoid fever, caused by infections with Salmonella Typhi, affects around 22 million people every year, causing more than 200,000 deaths. African countries are at particular risk of typhoid fever outbreaks.
A typhoid conjugate vaccine, Typbar-TCV®, has been licensed despite limited data on its efficacy. The Bill & Melinda Gates Foundation is supporting three trials – two in Asia and one in Malawi – to generate additional evidence on safety and efficacy.
The challenge
The THECA study complements the Gates Foundation trials by conducting two additional studies in Ghana and the Democratic Republic of the Congo (DRC).
The Ghana study is a randomised controlled trial that will generate data on safety and efficacy and population-level protection, adding to the pool of African data provided by the Malawi trial.
The DRC study, by contrast, will be embedded within a mass vaccination campaign, with a case-control design used to assess efficacy. This study will provide additional data on protection when the vaccine is used within routine public health systems, as well as valuable insight into feasibility, programmatic barriers and enablers, and cost-effectiveness.
The project
The THECA study will provide policymakers in Africa with additional data on the safety and efficacy of Typbar-TCV®, but also information on its performance in real-life settings and factors that influence its effectiveness in practice. This will enable them to make much more informed decisions on whether to introduce the vaccine and how to use it.
Impact
“
test the safety and efficacy of this new formulation in young children
”
Bringing antiretroviral drugs to children
The CHAPAS trials have ensured that many more children with HIV have benefited
from life-saving antiretrovirals.
EDCTP portfolio: HIV & HIV-associated infections
The challenge
Typhoid fever, caused by infections with Salmonella Typhi, affects around 22 million people every year, causing more than 200,000 deaths. African countries are at particular risk of typhoid fever outbreaks.
A typhoid conjugate vaccine, Typbar-TCV®, has been licensed despite limited data on its efficacy. The Bill & Melinda Gates Foundation is supporting three trials – two in Asia and one in Malawi – to generate additional evidence on safety and efficacy.
The THECA study complements the Gates Foundation trials by conducting two additional studies in Ghana and the Democratic Republic of the Congo (DRC).
The Ghana study is a randomised controlled trial that will generate data on safety and efficacy and population-level protection, adding to the pool of African data provided by the Malawi trial.
The DRC study, by contrast, will be embedded within a mass vaccination campaign, with a case-control design used to assess efficacy. This study will provide additional data on protection when the vaccine is used within routine public health systems, as well as valuable insight into feasibility, programmatic barriers and enablers, and cost-effectiveness.
The project
The later CHAPAS-3 trial compared the efficacy and safety of three fixed-dose combinations including two without stavudine (found to have some long-term side effects in adults, leading to a recommendation that its use be discontinued in children). The trial the first of its kind in Africa studied nearly 500 children at four sites in two African countries.
The THECA study will provide policymakers in Africa with additional data on the safety and efficacy of Typbar-TCV®, but also information on its performance in real-life settings and factors that influence its effectiveness in practice. This will enable them to make much more informed decisions on whether to introduce the vaccine and how to use it.
ratios forfixed-dose combinations and on appropriatedosage according to weight.
The CHAPAS-3 trial confirmed the effectiveness of fixed-dose combinations, providing further impetus to the rollout of antiretrovirals to children. Its evidence on abacavir informed the WHO recommendation of abacavir-containing combinations for first-line therapy in children. Trial data have also been used to support applications for regulatory approval for new scored efavirenz tablets.
Impact
L’homme RF et al. Nevirapine, stavudine and lamivudine pharmacokinetics in African children on paediatric fixed-dose combination tablets. AIDS. 2008;22(5):557–65.
Mulenga V et al. Abacavir, zidovudine, or stavudine as paediatric tablets for African HIVinfected children (CHAPAS-3): an open-label, parallel-group, randomised controlled trial. Lancet Infect Dis. 2016;16(2):169–79.
WHO. Guidelines on the use of antiretroviral drugs for treating and preventing HIV infection: recommendations for a public health approach. 2010.
WHO. Consolidated guidelines on the use of antiretroviral drugs
for treating and preventing
HIV infection: Recommendations for a public health approach
(second edition). 2016
Projects: Children with HIV in Africa Pharmacokinetics and Adherence of Simple Antiretroviral Regimens (CHAPAS): CHAPAS-1 and -3
Project lead: Professor Chifumbe Chintu, University Teaching Hospital, Zambia (CHAPAS-1); Dr Veronica Mulenga, University Teaching Hospital, Zambia (CHAPAS-3)
Target population(s): Children with HIV
Sample size: 71 (CHAPAS-1); 480 (CHAPAS-3)
Countries involved: Ireland, the Netherlands, the UK, the USA, Zambia (CHAPAS-1); Uganda, Zambia (CHAPAS-3)
Project duration: 2005–2009 (CHAPAS-1); 2010 –2011 (CHAPAS-3)
EDCTP funding: €1.2M (CHAPAS-1); €4.6M (CHAPAS-3)
Total project funding: €1.2M (CHAPAS-1); €5.0M