Hopes rise for new TB vaccine after early trial shows 'astonishing' results

The BCG is the only the vaccine currently available for TB and was developed more than 100 years ago. Although it protects children from certain types of the disease, the jab does not protect adults or adolescents. 

TB is the “quintessential disease of poverty” and thrives among crowded communities with poor sanitation.

In 2018, there were some 10 million new infections globally – a figure that has barely changed in recent years. 

Treatment options for TB are notoriously arduous, with patients having to take a cocktail of drugs over a six-month period, while untreatable drug-resistant infections are on the rise. 

Experts are therefore placing increasing focus on tools to prevent new infections and believe the new vaccine could save millions of lives. 

Although a 50 per cent success rate may seem low – the measles vaccine is 98 per cent effective – it is a significant improvement on the BCG and has been described as a “truly astonishing” result. 

“We are one more cautious, but exciting, step closer to a vaccine for TB,” said Dr Paula Fujiwara, scientific director of the International Union Against Tuberculosis and Lung Disease. “A vaccine is the ultimate prevention tool and the announcement today is welcome news.”

The new vaccine, M72/AS01, is made up of proteins from bacteria which trigger an immune response, and has been developed by UK pharmaceutical giant GSK and non-profit organization IAVI. 

The trial, which took place in Kenya, South Africa and Zambia, involved just over 3,500 HIV-negative adults with latent TB – a silent infection that progresses to active TB in roughly 10 per cent of cases. About one quarter of the world’s population unknowingly has latent TB. 

In the trial, participants were given either the vaccine or a placebo in two doses, 30 days apart. The final analysis showed that 13 people in the vaccine group developed active pulmonary TB, compared to 26 in the placebo group.

“This is an exciting development towards a vaccine, which could effectively prevent tuberculosis infection and disease,” Dr Tim Wingfield, a TB expert at the Liverpool School of Tropical Medicine who was not involved in the trial, told the Telegraph.  

But he said that more trials are needed to confirm the initial findings. 

“The next vital steps will be to evaluate the impact and durability of the vaccine in preventing tuberculosis disease in real-world, rather than clinical trial, settings,” he said.

This needs to include other regions of the world and different sub-populations, particularly those who are malnourished or extremely poor, Dr Wingfield added. 

According to GSK, the next stages of the trial are yet to be confirmed but conversations are taking place to work out how to move the vaccine forward. Larger studies will be required to secure regulatory approval, which is likely to take years.

“As researchers discuss how to move the trial into its final phase, we simultaneously need to be doing all we can to prevent tuberculosis with medications that we already have at our disposal,” said Dr Fujiwara.

At a press conference held during the conference in India, Ann Ginsberg from IAVI called the trial results “groundbreaking”.

Peter Kim, from the National Institutes of Health in the US added: “The results are truly astonishing worthy of applause and celebration.

“An effective vaccine against TB is exactly the type of game-changer we need to end TB epidemic once and for all.”