Pune: Two new vaccines have shown promising results amid India’s struggle with the world’s highest burden of tuberculosis (TB) at 27%.A study was published in the British Medical Journal (BMJ) on April 9 regarding the efficacy of the two new vaccines — VPM1002 developed by the Serum Institute of India in Pune and Immuvac manufactured by Cadila Pharmaceuticals Ltd — in tackling TB. The study said that VPM1002, a genetically modified recombinant Bacillus Calmette-Guérin (BCG) vaccine, displayed 50.4% effectiveness against extrapulmonary TB (EPTB) across all age groups and vaccine effectiveness of 79.5% among those aged 36-60 years, suggesting a potentially major public health benefit.About 22% of the total TB cases reported in the country are EPTB. It not only affects the lungs, but other organs like lymph nodes, pleura, abdomen and spine. The condition presents diagnostic challenges due to its paucibacillary (presence of very few bacteria in the body) nature, despite advanced diagnostics like Xpert MTB/RIF. EPTB is associated with high morbidity due to the difficulty in diagnosis and treatment.Currently, BCG is the only licenced vaccine against TB. Though it is effective against severe forms in young children, it does not offer protection to adolescents and adults. The recent study included vulnerable household contacts around 6 years old and above, irrespective of comorbidities and risk factors.The study in BMJ found that both the vaccines are safe, but did not show any efficacy against all forms of microbiologically confirmed TB or pulmonary TB (PTB). The vaccines demonstrated over 65% efficacy against EPTB in people with latent TB infection — 64.9% for VPM1002 and 66.3% for Immuvac.Another key finding is protective efficacy in children and adolescents against PTB and EPTB. VPM1002 showed over 60% protective efficacy againstall TB, PTB and EPTBin 6 to 14 years age group. Immuvac provided over 60% vaccine efficacy against EPTB only in children aged between 6 and 10 years age. It is indicative of stronger benefits in high-risk and younger populations.However, neither vaccine protected underweight children and adults, suggesting that nutritional support may be needed along with vaccination — especially for younger children.Neither vaccine offered general protection against TB or prevented latent TB infection, both demonstrated an ability to prevent the progression to active TB in those who developed latent TB at 6 months. VPM1002 provided around 60% efficacy against all TB, PTB and EPTB, while Immuvac provided about 50% efficacy against all TB and EPTB.The study was led by researchers, including Manjula Singh of Indian Council of Medical Research andRandeep Guleria, Rohit Sarin, Sindhu Joshi, Sanghamitra Pati and others.Meanwhile, advocate for public healthcare Dr Anant Phadke said the vaccines could be useful in the broader strategy of control and elimination of TB in India. “According to the study, it gives protection to around 50% of children (aged 5 to 18), who are not malnourished and are household contacts of sputum-positive TB patients. Improving nutrition and housing must be the mainstay of TB control and elimination,” he added.
