New Delhi: The Serum Institute of India (SII) has signed an agreement to manufacture what it says has the potential to be the first new tuberculosis (TB) vaccine in more than a century, if ongoing clinical trials are successful.
The only licensed TB vaccine available today is the Bacillus Calmette-Guérin (BCG) vaccine, which was originally developed in 1921.
The Pune-based vaccine maker, known for manufacturing Covishield, the Indian brand of the Oxford-AstraZeneca COVID-19 vaccine, will now manufacture a new experimental TB vaccine called M72/AS01E under an agreement with the Gates Medical Research Institute (Gates MRI). The vaccine is currently being evaluated in a Phase III clinical trial involving 20,000 participants across South Africa, Kenya, Malawi, Zambia and Indonesia.
“This partnership represents an important step towards ensuring countries with a high TB burden can access the vaccine as quickly as possible if it proves successful,” Gates MRI and SII said in a joint statement announcing the agreement.
Tuberculosis remains the world’s deadliest infectious disease despite being preventable and curable. Caused by the bacterium Mycobacterium tuberculosis, TB usually affects the lungs and spreads through the air when a person with active TB coughs, sneezes or speaks.
According to the World Health Organization (WHO), an estimated 10.7 million people developed TB in 2024 and around 1.23 million died from it. India accounts for nearly one in every four TB cases globally, making it the country with the highest TB burden.
How new vaccine works, why it is needed
Since its advent in 1921, BCG has remained the most widely used vaccine despite its limitations and highly variable efficacy. It is routinely given to newborns in India because it protects infants against severe forms of TB.
According to Gates MRI, the BCG vaccine offers limited protection against pulmonary TB—the form that drives most transmission, particularly among adolescents and adults.
M72/AS01E has been designed specifically to fill this gap. The vaccine targets people with latent TB infection—those who carry dormant bacteria without symptoms, estimated at around a quarter of the world’s population—and aims to stop the infection from progressing to active disease.
It combines an antigen called M72, a protein from the TB bacterium that helps the immune system recognise the infection, and AS01E, an adjuvant developed by British pharmaceutical company GlaxoSmithKline (GSK) that boosts the body’s immune response.
An adjuvant is a substance or treatment that enhances, improves, or adds to the effectiveness of a primary therapy, drug or any active treatment.
According to WHO, a vaccine offering around 50 percent protection against pulmonary TB in adults could prevent 76 million new cases, save 8.5 million lives, and cut TB-related household costs by more than $41.5 billion over 25 years.
Betting ahead of trial results
Ordinarily, manufacturers wait until a vaccine clears Phase III trials and wins regulatory approval before committing to large-scale production.
“Initiating this work well ahead of Phase 3 trial results is a deliberate strategy to ensure readiness to produce and distribute the vaccine and begin meeting global demand as quickly as possible, should the trial be successful and regulatory approvals be granted,” Gates MRI and SII said in their joint statement.
Under the agreement, SII will manufacture the M72 antigen component while GSK continues to supply the AS01E adjuvant, with both sides coordinating on demand forecasting and supply planning. “SII expects to invest more than US$100 million of its own resources to strengthen manufacturing readiness and capacity building to support potential future supply,” the vaccine manufacturer said.
Status of trials
The ongoing Phase III trial began in March 2024 and completed enrolment in April 2025 across 54 sites in the five participating countries.
In an earlier Phase II-B trial involving 3,575 adults, the vaccine reduced the risk of developing active lung TB by about 50 percent over three years, results widely regarded as the most promising in TB vaccine research in decades. The study included adults aged 18-50 years who had latent TB infection but not HIV.
“Results of the trial are anticipated in late 2028 with global and local regulatory submissions starting in 2029, if the vaccine is proven to be well tolerated and efficacious,” Gates MRI said.
(Edited by Amrtansh Arora)
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