TITLE:
Candidate Vaccines against Tuberculosis and the Future of Novel TB Vaccine Research
AUTHORS:
Ochran Chetty, Cohen Chetty
KEYWORDS:
Tuberculosis, Novel TB Vaccines, Clinical Trials, Bacillus Calmette-Guérin (BCG), Tuberculosis Prevention
JOURNAL NAME:
Journal of Tuberculosis Research,
Vol.10 No.4,
December
29,
2022
ABSTRACT: Introduction: Tuberculosis (TB) continues to be a global health
challenge and currently only one licensed vaccine is available. For nearly 100
years, the Bacillus Calmette-Guérin (BCG) vaccine has been in use. While it
provides protection against disseminated TB in infants, its protection against
adult and adolescent pulmonary tuberculosis
(PTB) is variable. This literature review will provide an overview of the
clinical status of candidate TB vaccines and discuss the challenges and future
development trends of novel TB vaccine research, in combination with a general
overview of the Tuberculosis (TB) disease and Mycobacterium tuberculosis
itself. Methods: Bibliographic searches were carried out on medical
journal databases, publishers, and aggregators. The most used databases
were PubMed, NCBI and MDPI. Publications in English on these and other
databases relating to novel TB vaccines were included in this review. Results: Currently, there are 12 main vaccine candidates in various phases of clinical trials, they include four protein or adjuvant
vaccines, three viral-vectored vaccines, three mycobacterial whole cells or
extract vaccines, and one each of the recombinant life and the attenuated
Mycobacterium tuberculosis vaccine. Currently, the most likely candidate
vaccines are the M72 + AS01E and Vaccae vaccines. M72 + AS01E is a recombinant fusion protein vaccine candidate,
clinical trials showed that administering two doses of M72/AS01E was successful in reducing the
development of active TB disease with 50% efficacy. Studies have also proven the efficacy of Vaccae (which is currently in
phase III clinical trials) as an adjunctive therapy, with it being curative in
conjunction with current therapy. Conclusion: Given the morbidity and
mortality suffered globally by M. tuberculosis, it is time to realize the seriousness of the
situation and accelerate our commitment and investment to the eradication of
this infectious disease. With the number of vaccine candidates currently
in clinical trials having promising results, it is imperative to continue these
studies and accelerate towards phase III licensure trials if we are to achieve
the milestone of “End TB Strategy” by 2035. Today, we are witnessing immense progress in both preclinical
and clinical TB vaccine research despite disappointing results from some of the
clinical efficacy trials like that of MVA85A. We can revisit the design of
vaccines and learn from them. It is important not only to recognize and give
credit to those that have tested well in human trials, such as M72 + AS01E, but
to expedite and improve its efficacy through funding of its research.