VPM1002, a genetically modified tuberculosis vaccine meant to improve on the century-old BCG shot, failed to prove itself at least as effective as BCG in a phase 3 trial of nearly 6,900 newborns across five African countries. [1]

The trial, published in The Lancet Infectious Diseases, enrolled infants in Gabon, Kenya, South Africa, Tanzania and Uganda, randomizing them to VPM1002 or standard BCG. The primary goal was showing VPM1002 was no worse than BCG at preventing TB infection, measured by a blood test called QFT conversion. It fell short: 5.3 percent of VPM1002 recipients converted versus 4.3 percent on BCG, and the statistical margin needed to claim non-inferiority wasn't met. [1]

BCG, introduced in 1921, remains the only licensed TB vaccine, protecting young children against severe disease but losing effectiveness in adolescents and adults. The World Health Organization has pushed development of successors; VPM1002 is one of 17 candidates in the pipeline against a disease that killed an estimated 1.2 million people globally in 2024. [1]

Fewer infections occurred than the trial was designed to detect — 334 QFT conversions instead of the 632 required — leaving the result short of definitive. The trial was halted early in October 2024 on a safety board's recommendation, though safety profiles for both vaccines were similar. Oxford vaccinologist Helen McShane, commenting in the same journal, wrote that the results show "there are no obvious short cuts in tuberculosis vaccine efficacy trials." [1]

-- KENJI NAKAMURA, Tokyo