As the world observes World TB Day on March 24, a significant breakthrough emerges in the battle against tuberculosis (TB), a disease that claims approximately 3 500 lives daily, as reported by the World Health Organization (WHO).
Experts are heralding the potential of a new vaccine, M72/AS01E, which is currently undergoing a pivotal phase 3 clinical trial, aimed at determining its efficacy in preventing TB disease.
This critical trial is being conducted across five countries, South Africa, Zambia, Malawi, Kenya, and Indonesia, with South Africa housing the majority of trial sites.
Professor Willem Hanekom, an esteemed TB vaccine specialist and executive director of the Africa Health Research Institute, acknowledges the grave socio-economic toll that TB takes on communities, particularly in sub-Saharan Africa.
“The world’s highest incidence rate is here, where hundreds of thousands fall ill each year,” he emphasises.
Hanekom points out that it is fitting that, as the global community focuses on TB awareness today, Africa, primarily South Africa, is playing a pivotal role in the advancement of a TB vaccine that shows promise akin to that of the BCG vaccine, which was developed over a century ago in 1921.
The BCG vaccine, while a staple in infant health, has shown limited effectiveness in adults and adolescents, who are the primary transmitters of the disease. It is revealed that the M72/AS01E is being closely watched not just for its potential to mitigate immediate health crises but also for its far-reaching socio-economic benefits outlined by the WHO:
- A significant decrease in TB incidence rates and associated mortalities, alongside a reduction in the prevalence of drug-resistant strains of the disease.
- The economic advantage gained through cost-effective immunisation, which could alleviate future TB treatment expenditures, especially in countries with high TB rates, such as South Africa.
- Progress towards health equity, as the vaccine aims to prevent TB in impoverished and underserved communities, aligning with universal health coverage goals.
- Advancement of various UN Sustainable Development Goals (SDGs), encompassing the eradication of poverty and hunger and enhancement of global health and employment opportunities.
- Encouragement of increased investment in TB research, potentially speeding up the availability of effective vaccines.
Initial reports already exhibit promising results for M72/AS01E, which demonstrated an acceptable safety profile and a 50% efficacy in phase 2b trials, with further analyses suggesting up to 68% effectiveness, far surpassing the WHO’s minimum efficacy requirement for new TB vaccines. However, these findings must be validated through the ongoing phase 3 trial, which is a double-blind study set to involve 20 000 participants; over 19 000 individuals have already been enrolled. The trial’s completion is projected for 2027 or 2028.
Spearheaded by the Gates MRI, a non-profit entity associated with the Gates Foundation, the phase 3 trial benefits from substantial support from both the Gates Foundation and Wellcome, with GSK collaborating by supplying the necessary adjuvant for the vaccine's trials and potential distribution.
Despite the promising vaccine developments, challenges remain. The integration of adolescent and adult vaccinations into existing health systems, traditionally focused on infant BCG administration, needs addressing. Further hurdles included vaccine hesitancy within target communities and the specific requirements of some countries for domestically-manufactured vaccines. Ascertaining vaccine demand remains complex, which could hinder investment in production facilities upon approval.
Hanekom further maintains that optimism, asserting that vaccination simplifies TB control compared to current treatment and prevention strategies. “There is no question: vaccination is the only way we can bring TB completely under control,” he states.
Saturday Star