India chasing new TB vaccines after 100 years

NEW DELHI: Chasing India’s target of eliminating tuberculosis by 2025, scientists at the Indian Council of Medical Research have recruited about 12,000 participants for a phase III study of two potential vaccines.

The researchers want to see how effective the vaccines are in preventing the disease in adult household members of a person newly diagnosed with TB. The participants from across seven sites in India will be monitored for three years before the potential vaccines are approved for use commercially or under the national TB programme.

“Recruitment in the middle of a pandemic was a huge challenge for us because we had to motivate healthy people in a household where TB was detected to come to the DOTS centres for vaccination,” one of the scientists said on condition of anonymity. DOTS, or directly observed treatment, is the name given to the TB control strategy recommended by the World Health Organization.

“For Covid-19 vaccines and therapeutics, the initial results can start coming in within months,” the researcher said. “But TB is a long-term illness, and we will have to observe the participants for a longer duration to arrive at any result.”

One of the vaccines being tested to prevent tuberculosis of the lungs is Immuvac, which was developed to prevent leprosy. Immuvac, also known as mycobacterium indicus pranii, displays antigens similar to both the leprosy bacterium and the TB bacterium.

The other vaccine candidate is VPM1002, a recombinant BCG that is a widely used vaccine in the world.

The new vaccine developed in Germany has the genetic code of the BCG edited in a way that leads to better availability of the TB antigens, thus training the immune system to better fight tuberculosis.

Another trial of the same candidate is underway to prevent recurrence of TB in adults. VPM1002 is also being tested to see whether it can offer protection against Covid-19.