Australian researchers are confident a new and more effective tuberculosis vaccine could be developed in the next five years.
Tuberculosis (TB) is a disease caused by an infection of mycobacterium tuberculosis and is a leading cause of death worldwide, killing 1.5 million people in 2020 according to the World Health Organization.
The Centenary Institute and University of Sydney as well as several international research teams were awarded $19 million to develop and bring a vaccine to the point of human trials.
Angelo Izzo, senior research scientist with the Centenary Institute, said while cases were low in Australia, areas such as far north Queensland and Torres Strait are at high risk due to their proximity to countries such as Papua New Guinea.
"It doesn't take that much of a stretch to think that it could easily come into Australia and disseminate very, very easily throughout the populations and then move down throughout the country," Professor Izzo said.
A century-old vaccine
Professor Izzo said the only current vaccine, known as the Bacille Calmette-Guérin (BCG) vaccine, was more than 100 years old and its effectiveness had waned.
While still generally effective in infants, he said the vaccine's effectiveness declined as the person aged.
"They then become susceptible as they get into their teens, and this is a time when they start to go out into the community and become really susceptible to tuberculosis," he said.
Professor Izzo said multi-antibiotic-resistant strains of TB, as well as the bacteria's capacity to sit dormant in a body for many years, also made it difficult to monitor and treat.
"It's kind of learnt to live with humans over the years. It's been around for a long, long time," he said.
"These new multi-drug-resistant tuberculosis strains that are springing up around the world tend to be more … virulent.
"Therefore, there's a much greater probability of leading to death as a result of the infection."
A systematic approach
The funding for the vaccine project will last for five years, enough time according to Professor Izzo for a vaccine to be ready for trial.
"We have a systematic way in which to approach this," he said.
"The crux of what we try to do with a vaccine is to pick apart the immune response that we need … that we can then build into a vaccine."
He said this was done through the combination of two components: antigens and adjuvants.
Antigens are proteins from the TB bacteria, while adjuvants are a common component of vaccines that can stimulate the immune response of humans.
"The question becomes, so which adjuvant does this best?" he said.
Professor Izzo said the understanding of adjuvants had greatly expanded in the past 10 to 15 years, which would help maximise the chance of generating a long-term immune response.
Even though the disease was not as common in countries such as Australia and the US, he said it was still an international problem that needed to be addressed.
"It's a global issue because we need to be able to control the spread of and limit the spread of tuberculosis," he said.
"Tuberculosis is predominantly a pulmonary infection, but it can literally infect any organ in the body.
"If you can prevent dissemination and you can prevent disease then that would be one of the optimal holy grails."
