Candidate vaccine could give TB the needle
A CANDIDATE tuberculosis (TB) vaccine study has renewed hope among researchers, with UCT experts describing the results as “ground-breaking”.
This as TB remains the number one killer disease in South Africa, according to Statistics SA’s latest “Mortality and Cause of Death” report released earlier this year.
The M72/AS01E Vaccine study, published in the New England Journal of Medicine, has yielded groundbreaking results which show that the vaccine has an efficacy of about 50%.
The investigational vaccine was tested on HIV negative adults with latent TB.
Professor Mark Hatherill, director of the SA Tuberculosis Initiative at UCT, described the findings as convincing. “This is particularly groundbreaking because these results showed for the first time that it’s possible for a new vaccine to protect people who are already infected with TB, from progressing from a state of infection to a state of disease, and that had never been shown before.”
Explaining the significance of the study’s findings, Hatherill said the study had an efficacy of around 50%.
“We already have a TB vaccine called BCG which is given to all babies at birth. BCG is partially effective at protecting babies and small children from the most severe forms of TB, but it doesn’t do much for protecting children against lung TB, and by the time children get to adolescence that protection has waned,” he said.
Hatherill said if adults were not effectively protected against TB, this was problematic as the rate of infection increased gradually.
“If we are looking at a strategy to have an impact in protecting these adults, we have to look for ways to protect adults who are already infected.
“It’s vitally important that we find a new vaccine that can protect adults who are not only the victims of the epidemic but are the drivers of the epidemic,” he said.
Meanwhile, experts say it’s vital that a new vaccine is developed as South Africa cannot afford to treat itself out of the epidemic.
The study enrolled more than 3 500 participants across 11 sites in southern and east Africa, including Kenya, Zambia and South Africa.
According to researchers, half of the participants were given the candidate vaccine while the other half were given a placebo vaccine.
In the participants who received the investigational vaccine, there were 10 cases of TB and in those who received the placebo, there were 22 cases of TB.
This represents 54% efficacy, Hatherill explained.
Honorary professor and director at the Wellcome Centre for Infectious Diseases Research in Africa at UCT, Robert Wilkinson, described the results as intriguing and overall highly encouraging.
“It was a proof-of-concept study of a new tuberculosis vaccine given to adults already thought to be infected. Overall it reduced the risk of tuberculosis by around 50%.”
Wilkinson said funding for TB research was “highly necessary”.
“Tuberculosis research is poorly funded by comparison with research on many other diseases.”
Wilkinson’s statement comes amid growing calls for more funding for TB research and development.
“It’s vitally important that there is much more funding directed towards TB prevention. It’s obviously important for TB patients that better diagnostics and treatments are sought, but in order to control this epidemic we need better tools for prevention and vaccines are the most effective tools for prevention,” said Hatherill.
Asked when the vaccine would be ready, Wilkinson said: “The final follow-ups are late this year. Although the trial findings are encouraging, many further trials showing similar efficacy would be necessary before the product could be licensed”.