TAG Statement on Results of the PreVenTB Phase III Trial of TB Vaccine Candidates VPM1002 and Immuvac
15 April 2026
CONTACT: Mike Frick, mike.frick@treatmentactiongroup.org
Well-conducted study sponsored by Indian Council of Medical Research did not meet primary efficacy endpoint of preventing microbiologically confirmed TB disease
April 15, 2026 — Treatment Action Group (TAG) acknowledges the long-awaited publication of results from the PreVenTB trial in the BMJ. PreVenTB was a randomized, double blind, placebo controlled phase III trial of two candidate TB vaccines — VPM1002 and Immuvac — funded and conducted by the Indian Council of Medical Research (CTRI/2019/01/017026). The trial enrolled over 12,700 participants at 18 sites in six Indian states.
VPM1002 is a live recombinant vaccine created by genetically modifying BCG, the world’s only existing vaccine against TB. It was originally developed in Germany and licensed to the Serum Institute of India. Immuvac is a vaccine based on heat-killed, whole-cell Mycobacterium indicus pranii (MIP), an organism closely related to Mycobacterium tuberculosis. (TAG’s Tuberculosis Vaccines Pipeline Report contains more information on each candidate.)
The trial assessed the efficacy, safety, and immunogenicity of VPM1002 and Immuvac compared with placebo over 38 months of follow-up.
Neither vaccine met the primary outcome — efficacy in reducing the incidence of microbiologically confirmed TB disease — when pulmonary and extrapulmonary TB were analyzed together. In the per protocol analysis, the efficacy of VPM1002 was estimated at 21.4% (95% CI -8.9 to 43.2) against all forms of TB and 19.5% (95% CI -14.6 to 43.4) against pulmonary TB; neither result was statistically significant. Immuvac did not protect against all TB or pulmonary TB.
Some stakeholders have highlighted glimmers of positive efficacy in the data, with most attention falling on two findings:
- Half as many participants in the VPM1002 arm developed extrapulmonary TB than in the placebo arm (12 versus 24 cases, respectively). Investigators reported this as VPM1002 showing efficacy of 50.4% (95% CI 0.8% to 75.2%) against extrapulmonary TB. Half as many people experiencing extrapulmonary TB is encouraging, but the wide confidence interval, which just barely avoids statistical nonsignificance by crossing zero, together with the relatively small number of events, merits cautious interpretation.
- Receipt of VPM1002 reduced the incidence of TB, pulmonary TB, and extrapulmonary TB among participants 6–14 years old. This finding should be interpreted within the context of the trial’s design and original statistical analysis plan. This was a post hoc analysis, meaning it was performed after data were seen, and the subgroup of participants analyzed here did not match the age bands in the pre-specified analysis by age (where the age groups were 6–18, 19–35, 36–60, >60). In the pre-specified age analysis, VPM1002 efficacy was not observed except in one age group (36–60) and only after a statistical correction was applied. Moreover, the efficacy against extrapulmonary TB among 6–14 year-olds was only significant after applying the same statistical technique, called “Haldane’s modification,” which is used when a small number of people experience an outcome.
There is more to unpack from the trial and the full set of results deserves much more discussion. In 2025, the Indian regulator, the Central Drugs Standard Control Organization, turned down Serum Institute of India’s application to register VPM1002.
Although the overall results are disappointing, there is a lot to appreciate about the trial.
- TAG commends ICMR for leading one of the largest TB vaccine trials of the 21st century and showing that high-TB-burden country governments can fund TB vaccine research implemented at a large-scale.
- ICMR designed the study to reflect the epidemiology of India’s TB epidemic by incorporating extrapulmonary TB into the primary endpoint, enrolling a high-risk population left out of other trials (household contacts of people diagnosed with TB), and including participants of diverse ages (anyone older than 6 six was eligible).
- The trial incorporated important substudies, including a secondary endpoint assessing vaccine efficacy against prevention of TB infection and the collection of immunogenicity data from a subset of participants.
- The trial protocol was reviewed by representatives from community-based organizations representing people affected by TB.
The search for a new TB vaccine that protects people against pulmonary TB disease continues. More governments should follow India’s example in funding advanced and thoughtfully designed clinical trials and publishing results that, whether positive or negative, move the field forward.
About Treatment Action Group
Treatment Action Group (TAG) is an independent, activist, and community-based research and policy think tank working to end the epidemics of HIV, tuberculosis (TB), and hepatitis C virus (HCV). TAG works to ensure that lifesaving science reaches the people who need it most by advancing research, strengthening community leadership, and promoting equitable access to prevention, treatment, and care.
Source: Treatment Action Group
