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In Other News - A New TB Vaccine Option
Offering Hope
Researchers at the University of Witwatersrand (Wits) have developed a candidate vaccine for tuberculosis (TB) using a gene-editing approach, offering South Africa a new tool in its efforts to treat and prevent the disease.
TB remains the leading cause of death by infectious disease globally, with South Africa having one of the highest incidence rates in the world. For almost a century, the BCG vaccine - the only existing effective vaccine - has been administered to infants to prevent TB, but no vaccine has shown lasting protection. This means that BCG does not protect teenagers and adults and has not been effective at eradicating TB, spurring researchers to look for novel TB vaccine candidates to replace or boost BCG.
Professor Bavesh Kana, the Head of the School of Pathology and former director of the Centre of Excellence for Biomedical TB Research at Wits University, contributed to the groundbreaking study.
Researchers sought to modify the BCG vaccine to make it more effective at controlling the growth of M. tuberculosis. Mice injected with the edited BCG vaccine had less M. tuberculosis growth in their lungs than mice that received the original vaccine. “We can now offer a new candidate vaccine in the fight against this deadly disease," says Prof Kana. "The work also demonstrates that gene editing is a powerful way to develop vaccines. This is particularly important for researchers working on vaccine development."
Prof Kana is a consultant for the Bill and Melinda Gates Medical Research Institute in Cambridge, USA. and has worked in several international institutions, including the University of Pennsylvania, the Russian Academy of Sciences in Moscow, Texas A&M University, the Public Health Research Institute in New Jersey and Harvard Medical School.
He studies TB with a focus on developing new drugs with a shorter treatment duration and fewer side effects. Prof Kana has received numerous local and international accolades for his outstanding contribution to science and the health of people suffering from TB.
Working Towards A TB-Free World
South Africa has committed to the achievement of the Sustainable Development Goal to end TB as an epidemic by 2030. To achieve this target, South Africa and other UN member states have committed to reducing TB cases by 80% and TB deaths by 90% by 2030, compared with 2015 levels.
According to the World Health Organization (WHO)’s 2023 Global TB Report, in 2022, 280 000 people in South Africa fell ill with TB – a reduction from from 552 000 TB cases in 2015. In 2022, 468 of every 100 000 people living in South Africa fell ill with TB, compared with 988 of every 100 000 people in 2015.
This equates to a 53% reduction in TB incidence between 2015 and 2030. Against the WHO’s targets, South Africa is in a strong position to achieve the SDG target to reduce TB incidence by 80% by 2030.
The report indicates South Africa still has some work to do in reducing TB deaths. Between 2015 and 2022, TB deaths in South Africa fell by 17%, less than the WHO’s End TB Strategy milestone target of a 20% reduction by 2020. According to the WHO’s latest data, 54 000 people in South Africa died of TB in 2022.
The report also indicated that 305 350 people in South Africa were started on preventive therapy in 2022, which is 5.6% less than the number of people started on preventive therapy in 2021 (321 610). “South Africa committed to the Sustainable Development Goal of ending the TB epidemic by 2030. While we are doing relatively well as a country – TB deaths have come down since 2015 – we need to do a lot better to reach the milestones,” says Prof Kana.
Prof Kana has lamented the funding gap in developing tools to eliminate TB – a disease which dates back over 9000 years. “Until recently, our diagnostic approaches were a century old. With some novel vaccine candidates in the pipeline, we can finally begin to adequately address this devastating illness.”
How Does The Vaccine Work?
When humans get sick, their body's defence system spots particular signs, called PAMPs (pathogenassociated molecular patterns) on the outside of bacteria, viruses, or other harmful germs. This helps the body tell the difference between invaders and their own cells, and then it starts fighting the infection. Vaccines work by looking like germs, so that they can start the first defence without making a person sick. This allows the person to build up immunity to the disease.
