In this blog, the author shares insights from their study, which discusses an affordable and effective Tuberculosis (TB) vaccine. With TB being a major concern in South Africa, this vaccine offers a promising and accessible solution, especially for individuals with HIV.
Tuberculosis (TB) has killed more people globally than any other single infectious disease over the last decade. The decline in global TB burden remains slow and inadequate despite routine bacille Calmette-Guérin (BCG) vaccinations of neonates and drug therapy. South Africa has one of the highest TB incidence rates, with HIV co-infection as an important driver of the epidemic. The M72AS01E vaccine candidate is the first in a century to show efficacy against active TB disease in adults in early phase clinical trials.
Our new study found that a suitably designed vaccination programme for this novel vaccine is likely to be highly cost-effective and affordable in South Africa considering the resource and budget constraints of the country.
The next step for the development process of the M72AS01E vaccine is to enter phase III clinical trials. To inform development strategies, policy and practice, we evaluated the epidemiological, health economic and budget impact of M72AS01E vaccination in South Africa, a strategically important setting for this vaccine due to the high TB incidence rate. We conducted two rounds of interviews with decision-makers in South Africa with expertise in TB, vaccines, and vaccination delivery across the government, academic, civil society and non-governmental sectors to determine appropriate vaccination implementation strategies, target population groups, and resulting resource implications. The full qualitative results from the first round of interviews were published in an earlier study. We subsequently mathematically modelled these strategies to estimate long-term resource requirements and health benefits arising from vaccination over 2025-2050. For the default-case scenario, we assumed 50% vaccine efficacy with a 5-year duration of protection.
After considering the constraints and preferences expressed by the decision-makers, we identified four possible vaccination implementation strategies: target either everyone aged 18–50, or all adults living with HIV(PLHIV), delivered either via a mass vaccination campaign followed by routine vaccination of 18-year-olds or dual mass vaccination campaigns 10 years apart. Delivering two mass campaigns 10 years apart to all 18-50-year-olds conferred the greatest net health benefit (highest overall population health increase) with a 65-70% probability of being cost-effective. This strategy would cost USD 507 million to deliver 38 million vaccine courses, reducing TB- related cost by USD 184 million. The reduced mortality among PLHIV will increase the utilisation of antiretroviral therapy (ART), increasing ART cost by USD 79 million compared to not implementing the vaccination programme.
Notably, the expert-proposed strategies that included a routine vaccination component produced lower net health benefits than the dual-mass campaigns. In terms of the target population, in a worst-case scenario where the vaccine is less effective (30% efficacy and 3-year duration of protection), a dual-mass vaccination campaign only targeting PLHIV produced the greatest net health benefit with a 65-83% probability of being cost-effective.
These results highlight engaging local stakeholders early in the vaccine development process can help to identify feasible and affordable vaccination scenarios.
