There’s an urgent need for effective new TB vaccines without which it would be impossible to attain a TB-free world by 2030
Vaccination was not a cornerstone of tuberculosis (TB) eradication programmes until now. But on April 6, 2023 the World Health Organisation (WHO) released a draft document outlining the global framework to prepare countries for the introduction of new TB vaccines for adults and adolescents.
The goals of the global framework are threefold; ensuring the availability of vaccines and doing so sustainably with a sufficient and timely supply chain, establishing an equitable delivery system beneficial to all and meeting the requirements of key stakeholders including policymakers, end-users and health systems.
After releasing the draft technical document, WHO is now seeking comments “to review this draft document and provide comments on both the general utility of the document, and the specific guidance developed for new TB vaccines”, until April 27 from all stakeholders, including the public.
Eradicating TB is a key health target of the United Nations Sustainable Development Goals (SDG). To realise it, the World Health Assembly passed a resolution, first in 2014, which was updated a year later, with three key aims in the blueprint: Reduce TB incidence by 80 per cent, TB deaths by 90 per cent and to eliminate catastrophic costs for TB-affected households by 2030.
The adult and adolescent populations see 90 per cent of all TB cases. So a targeted focus on “the main transmitters of pulmonary TB disease, is likely to have a significant impact not only on reducing TB transmission generally but also on infants, children, and other high-risk populations,” the draft document noted.
This is a critical step given the absence of a framework for an “established immunisation platform for vaccine delivery for adults and adolescents”.
While the bacille calmette-guérin (BCG) vaccine has been around for over eight decades and is a key component of national childhood immunisation programmes in several countries, it doesn’t help much with limiting disease transmission.
The BCG vaccine “does not prevent primary infection and, more importantly, does not prevent reactivation of latent pulmonary infection, the principal source of bacillary spread in the community,” according to WHO.
Moreover, the vaccine has shown poor effectiveness in preventing pulmonary TB in adolescents and adults. This characteristic only highlights the urgent need for effective new TB vaccines — which are expected to be available in the next three-five years — without which it would be impossible to attain a TB-free world by 2030, as envisioned by the UN’s SDGs.
“As several innovative TB vaccine candidates intended for use in adolescents and adults are either currently in or about to enter Phase III clinical trials, a vaccine for the prevention of TB disease in adolescents and adults could be available in the near term,” the latest draft technical document noted.
The WHO’s Preferred Product Characteristics for New Tuberculosis Vaccine outline two key requirements. The first deals with the vaccine providing protection to both adults and adolescents with and without evidence of latent Mycobacterium tuberculosis infection. The vaccine should have an efficacy of at least 50 per cent, where protection lasts at least two years and a booster every five-ten years. The second one aims to replace the existing BCG vaccine for infants with a safer, more effective and more efficiently produced version.
The draft document describes the approach to be “accelerated, coordinated, integrated, people-centred, equity-driven and evidence-based.” Sustained global / regional financing and political engagement is a key aspect which will allow for a rapid and equitable introduction and rollout of new TB vaccines.
In conclusion, the draft document notes “much of the planning for uptake at both the global and country levels will depend on and be driven by the countries, the level of engagement of key voices within the TB community, and the timely initiation of planning.”
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