New TB Vaccines Show Promise, But the Fight Isn’t Over
Two new tuberculosis (TB) vaccines, VPM1002 and Immuvac, have been found safe in a large Phase 3 trial conducted in India. The study, involving over 12,700 healthy household contacts of individuals with active TB, offers a nuanced picture of the future of TB prevention.
The Challenge of Tuberculosis
Tuberculosis remains a significant global health threat. In 2023, an estimated 10.8 million people worldwide were reported to have TB, with a 4.6% increase in new cases between 2020 and 2023. The existing BCG vaccine, while effective against severe forms of TB in young children, provides limited protection for adolescents and adults.
Trial Results: A Mixed Bag
The PreVenTB trial, published in The BMJ, revealed that neither VPM1002 nor Immuvac significantly reduced the overall incidence of microbiologically confirmed TB or pulmonary TB. However, VPM1002 demonstrated 50.4% efficacy against extrapulmonary TB (EPTB), a form of the disease that’s often more difficult to diagnose.
Immuvac showed 33.2% efficacy against EPTB, though this result was not statistically significant. Interestingly, a post-hoc analysis indicated stronger results for VPM1002 in children aged 6 to 14 years, with an efficacy of 64.6% against all forms of TB.
Why Extrapulmonary TB Matters
Extrapulmonary TB affects organs other than the lungs, such as the lymph nodes, bones and brain. It often presents with varied and non-specific symptoms, making diagnosis challenging. Effective vaccines targeting EPTB could significantly improve patient outcomes and reduce the burden of disease.
Beyond Prevention: Impact on Latent Infection
While neither vaccine prevented latent TB infection both demonstrated an ability to prevent progression to active TB in those who developed latent TB. This is a crucial finding, as latent TB represents a vast reservoir of infection.
The Role of BCG and Emerging Trends
Currently, BCG is administered to approximately 323 million newborns annually, primarily to protect against severe childhood TB. However, its effectiveness wanes over time. The development of new vaccines like VPM1002 and Immuvac represents a critical step towards more durable and effective TB prevention strategies.
Interestingly, the BCG vaccine is likewise being explored in cancer treatments, highlighting its potential beyond infectious disease control.
TB Incidence in the United States
According to recent data from the U.S. CDC, TB cases in the U.S. Experienced a sharp decline in 2020, followed by a rebound from 2021 through 2024, with a slight decrease in 2025. Despite this recent increase, the overall incidence rate remains among the lowest globally.
Frequently Asked Questions
Q: Are VPM1002 and Immuvac widely available?
A: No, these vaccines are still under evaluation and are not yet widely available.
Q: What is extrapulmonary TB?
A: Extrapulmonary TB affects organs other than the lungs, making diagnosis more difficult.
Q: Is BCG still important?
A: Yes, BCG remains the only licensed TB vaccine and is widely used, particularly for infants in high-incidence countries.
Q: What were the side effects of the new vaccines?
A: Both vaccines were well-tolerated, with mild local reactions occurring in about one-third of recipients.
Did you realize? VPM1002 showed particularly strong efficacy against extrapulmonary TB in participants with positive tuberculin skin tests, demonstrating around 65% efficacy.
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