The final results of a three-year phase II clinical trial of a tuberculosis vaccine has shown 49.7 per cent efficacy in preventing pulmonary tuberculosis (TB) infection. Although there are about 15 developers globally working to create the TB vaccine, the latest results hold significance as this is the first time such results have been drawn in the last 100 years of research.
The vaccine is, however, a long way from being launched in India, with further trials required on the country’s population before it is rolled out.
The study, titled ‘Final Analysis of Trial of M72/AS01 Vaccine to Prevent Tuberculosis’, was published in the New England Journal of Medicine on Tuesday. The findings suggest the vaccine will help prevent infection risk by 50 per cent in the latent TB population, and come a day ahead of The 50th Union World Conference on Lung Health in Hyderabad. The global conference is scheduled to begin on October 30 and will run till November 2.
Latent TB means the TB bacteria is present in the body but remains dormant.
Between August 2014 and November 2015, 3,575 non-HIV positive people with latent TB and aged 18 to 50 years were enrolled for the trial in Kenya, South Africa and Zambia. While India was considered for the trial, researchers said sub-Saharan Africa was finally chosen due to higher TB incidence.
Half of latent TB population was given two doses of M72/AS01 vaccine a month apart. Three years later, of 1,626 people, 13 in the group developed active TB infection as opposed to 26 in the other group, which was given a placebo drug.
“The vaccine provided a high-level response in body. It generated antibodies to fight the bacteria. The efficacy remained constant until three years of trial,” said Olivier Van Der Meeren, the study’s co-author and the director of research and development at Glaxo Smith Kline.
Ann Ginsberg, the study’s co-author and technical advisor at International AIDS Vaccine Initiative (IAVI), which funded the trial, said the blood markers of patients who tested TB positive will now be analysed to understand how immune response works. “We don’t know what caused tuberculosis in these patients. More research is needed to understand immunological responses to the bacteria,” she said.
Meanwhile, Paula I Fujiwara, scientific director at The Union, said, “This trial brings us a step closer to a tuberculosis vaccine. Prevention is an important tool, but we also need medication simultaneously to prevent the disease burden.”
About 30-40 per cent of India’s population is infected by latent TB.
The World Health Organisation on Tuesday announced it will facilitate an expert meeting of developers, funders and countries to take the trials forward.
(The correspondent was invited to The 50th Union World Conference on Lung Health by Stop TB Partnership and The Union)
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