From the newsletter
The first doses of the tuberculosis vaccine candidate MTBVAC have been administered in South Africa, marking a key step in testing its safety and efficacy. The Phase 2b trial will enrol approximately 4,300 participants with latent TB infection across 15 sites in South Africa, Kenya, and Tanzania.
Tuberculosis (TB) is a major infectious disease in Africa and climate change is exacerbating the epidemic. It increases risks such as food insecurity and displacement, which heighten vulnerability to TB, according to the World Health Organization.
The century-old BCG vaccine offers limited efficacy, protecting only specific age groups. While it effectively shields infants from severe forms of tuberculosis, it becomes less effective against pulmonary TB, which is the most common type in older children and adults.
More details
The International AIDS Vaccine Initiative (IAVI) and the Spanish biopharmaceutical company Biofabri are key stakeholders in the IMAGINE (Investigation of MTBVAC toward Accelerating Global Immunization for a Neglected Epidemic) clinical trial. This large-scale safety and efficacy study is funded by Open Philanthropy, the Gates Foundation, and the German Federal Ministry of Education and Research. The IMAGINE trial will evaluate the safety and efficacy of MTBVAC in preventing active TB lung disease in adults.
The study will be conducted at 15 clinical research sites across Kenya, Tanzania, and South Africa. Notable locations include the Kenya Medical Research Institute in Nairobi, the Victoria Biomedical Research Institute in Kisumu, and the Ifakara Health Institute in Dar es Salaam. In South Africa, sites such as the Aurum Institute in Rustenburg and Tembisa, Be Part Research in Paarl. There are also various facilities in Cape Town, including TASK Delft and the University of Cape Town Lung Institute.
MTBVAC was developed by Carlos Martin from the University of Zaragoza and Brigitte Gicquel from the Institut Pasteur, with Biofabri leading its development. Unlike the current BCG vaccine, which derives from a cattle strain of TB, MTBVAC is made from a weakened form of human tuberculosis. It has been tested in both adults and newborns, demonstrating similar or superior immune responses and safety when compared to BCG. Biofabri is currently conducting a Phase 3 trial in newborns across South Africa, Madagascar, and Senegal. Additionally, a Phase 2a trial involving individuals both with and without HIV commenced in January 2024.
The BCG vaccine was originally developed by Albert Calmette and Camille Guérin and first administered to humans in 1921. It remains the only vaccine that effectively prevents tuberculosis (TB) and is typically included in the routine immunisation schedule for newborns. In Africa, the standard BCG vaccine regimen consists of a single dose given to infants at birth. It is administered as an intradermal injection of 0.05 ml for children under one year old, in accordance with WHO recommendations.
Currently, the vaccine is regarded as "weak" against TB due to varying effectiveness across different populations and age groups. Studies indicate that BCG can provide protection ranging from 0% to 80%, depending on the population and specific TB strain. While BCG has been shown to be effective against severe forms of TB, such as TB meningitis in children, it often provides inadequate protection against the most prevalent form of TB in adults, which is pulmonary TB.
Our take
Despite the worsening impacts of climate-driven displacement and malnutrition, tuberculosis is often overlooked in climate-health discussions in Africa. This oversight creates a dangerous gap in addressing a growing global health crisis. TB affects approximately 2.5 million people in Africa each year, accounting for roughly a quarter of all new TB cases globally and making Africa the region with the highest burden of TB cases per capita.
Displaced individuals living in overcrowded conditions face a higher risk of TB due to interrupted treatment and inadequate care. Malnutrition, worsened by droughts linked to climate change, further increases susceptibility to TB. With severe food insecurity and rising drought frequency in parts of Africa, particularly in the Sahel region, people become even more vulnerable to the disease.
Despite these alarming connections, TB remains underfunded. Each year, the African region requires at least $1.3 billion for TB prevention and treatment. However, countries contribute only 22% of the necessary budget, while external funding covers 34%. The remaining budget is left unfunded. Without climate-conscious investments in TB research, these underfunded programmes may become further strained, putting millions at risk.