Serum Institute Joins Global Race for First New TB Vaccine in a Century (M72/AS01E): Key Features, Clinical Trials, Significance

Why in News ?

The Serum Institute of India (SII) has entered into a strategic partnership with the Gates Medical Research Institute (Gates MRI) to manufacture M72/AS01E, a promising tuberculosis (TB) vaccine candidate currently undergoing Phase III clinical trials. If approved, it could become the first new TB vaccine in more than 100 years, after the Bacille Calmette-Guérin (BCG) vaccine.

Key Highlights

Partnership Between Serum Institute and Gates MRI

• Serum Institute of India has signed an agreement with Gates Medical Research Institute to manufacture the M72/AS01E TB vaccine candidate. 
• SII will invest over US$100 million to expand manufacturing infrastructure and prepare for large-scale production. 
• Gates MRI will transfer the vaccine antigen manufacturing technology to SII. 
• British pharmaceutical company GSK will continue supplying the AS01E adjuvant, which enhances the body's immune response. 
• Manufacturing preparations are being undertaken before regulatory approval to enable rapid global distribution if the vaccine is approved.

About M72/AS01E Vaccine

• M72/AS01E is a protein subunit vaccine candidate designed to prevent progression from latent TB infection to active pulmonary tuberculosis. 
• It is intended primarily for TB-infected, HIV-negative adults. 
• Originally developed by GlaxoSmithKline (GSK). 
• Development rights were later transferred to the Gates Medical Research Institute. 
• Supported by the Bill & Melinda Gates Foundation and Wellcome Trust.

Clinical Trial Status

Phase IIb Trial

• Conducted on 3,575 participants. 
• Demonstrated approximately 50% efficacy in preventing progression to active pulmonary TB. 
• Protection observed over a three-year follow-up period. 
• Participants were HIV-negative adults aged 18–50 years. 

Phase III Trial

• Began in March 2024. 
• Around 20,000 participants enrolled. 
• Conducted across 54 trial sites. 
• Countries involved : 
  • South Africa 
  • Kenya 
  • Malawi 
  • Zambia 
  • Indonesia 
• Participant enrolment was completed in April 2025. 
• The trial aims to establish the vaccine's safety, efficacy, and effectiveness.

Projected Global Impact

According to estimates by Serum Institute and Gates MRI, a vaccine with similar efficacy could :

• Prevent approximately 76 million new TB cases over 25 years. 
• Save nearly 8.5 million lives. 
• Generate around US$41.5 billion in economic savings for TB-affected households. 
• Significantly reduce healthcare costs in low- and middle-income countries.

Why is a New TB Vaccine Important ?

Tuberculosis remains one of the world's deadliest infectious diseases.

Global Burden (WHO, 2024)

• Nearly 11 million people developed TB. 
• Approximately 1.23 million deaths occurred due to TB. 
• TB remains the leading cause of death from a single infectious disease worldwide. 
• It continues to be among the Top 10 causes of death globally. 

High-Burden Countries

Major countries with the highest TB burden include :

• India 
• Indonesia 
• Philippines 
• China 
• Pakistan 
• Nigeria

Why Has TB Vaccine Development Been Difficult ?

Unlike COVID-19 vaccines, TB vaccine development has taken decades because :

• Mycobacterium tuberculosis has a highly complex biology. 
• TB bacteria can remain dormant for years as latent infection. 
• The immune response required for long-lasting protection is not fully understood. 
• Lack of reliable immune correlates of protection. 
• Conducting long-duration efficacy trials is expensive and time-consuming.

India's Role in Global Vaccine Manufacturing

• Serum Institute of India is among the world's largest vaccine manufacturers. 
• It has supplied affordable vaccines to more than 170 countries. 
• Played a major role during the COVID-19 pandemic by producing large quantities of vaccines. 
• Plans to collaborate with manufacturers in Indonesia and South Africa to strengthen long-term global vaccine supply chains.

Other TB Vaccine Candidates Under Development

Immuvac (MIP)

• Developed by : Indian Council of Medical Research (ICMR)  ,Cadila Pharmaceuticals 

MTBVAC

• Developed by : University of Zaragoza (Spain) ,Biofabri 
• In partnership with Bharat Biotech (India).

WHO's TB Vaccine Accelerator Council

• Established in 2023 by WHO Director-General Dr. Tedros Adhanom Ghebreyesus. 
• Objective : 
  • Accelerate TB vaccine research. 
  • Facilitate regulatory approvals. 
  • Improve manufacturing capacity. 
  • Ensure equitable global access to future TB vaccines. 

About Bacille Calmette-Guérin (BCG) Vaccine

• Introduced in 1921. 
• Currently the only licensed TB vaccine. 
• Developed by French scientists Albert Calmette and Camille Guérin. 
• It is a live attenuated vaccine derived from Mycobacterium bovis. 
• Provides strong protection against severe childhood TB, including : 
  • TB meningitis 
  • Miliary tuberculosis 
• Offers limited and variable protection against pulmonary TB in adults. 
• Included under India's Universal Immunisation Programme (UIP). 

Tuberculosis (TB): Overview

Causative Organism :- Mycobacterium tuberculosis 

Mode of Transmission :- Airborne infection through droplets released when an infected person coughs, sneezes, speaks, or sings. 

Commonly Affected Organ :- Lungs (Pulmonary TB) 

Other Forms

• Extrapulmonary TB affecting : 
  • Brain 
  • Bones 
  • Kidneys 
  • Lymph nodes 
  • Spine 

Symptoms

• Persistent cough (more than two weeks) 
• Fever 
• Night sweats 
• Weight loss 
• Fatigue 
• Coughing blood 

Diagnosis

• Sputum microscopy 
• CBNAAT/GeneXpert 
• Truenat 
• Chest X-ray 
• Culture tests 

Treatment

• Multi-drug antibiotic regimen under National TB Elimination Programme (NTEP). 
• Drug-resistant TB requires longer and more complex treatment. 

India's TB Elimination Initiatives

• National TB Elimination Programme (NTEP) (formerly RNTCP) 
• Nikshay Portal 
• Nikshay Poshan Yojana 
• TB Mukt Bharat Abhiyan 
• Universal Drug Susceptibility Testing (UDST) 
• Active Case Finding (ACF) 
• Free diagnosis and treatment through public health facilities. 
• Target to eliminate TB by 2025, five years ahead of the WHO End TB Strategy target of 2030. 

Significance

• Could become the first major breakthrough in TB vaccination in over a century. 
• Strengthens India's position as the global vaccine manufacturing hub. 
• Supports SDG 3 (Good Health and Well-being). 
• Promotes equitable access to affordable vaccines in developing countries. 
• May significantly reduce TB-related mortality, poverty, and healthcare expenditure. 

Challenges

• Successful completion of Phase III clinical trials. 
• Regulatory approvals across countries. 
• Large-scale manufacturing and financing. 
• Cold-chain logistics and equitable distribution. 
• Monitoring long-term effectiveness and safety. 
• Addressing drug-resistant TB alongside vaccination. 

Conclusion

The collaboration between the Serum Institute of India and the Gates Medical Research Institute marks a significant milestone in the global fight against tuberculosis. If the M72/AS01E vaccine successfully completes Phase III trials and secures regulatory approval, it could become the first new TB vaccine in over a century, substantially reducing the global TB burden while reinforcing India's leadership in vaccine innovation, manufacturing, and global public health.