article · Science
Bacillus Calmette-Guérin, commonly known as BCG, is widely used to protect children against human tuberculosis and contains attenuated Mycobacterium bovis. Although known to offer protection to livestock against bovine tuberculosis, its precise effectiveness in cattle had not been quantified. Through a natural transmission trial over a one-year exposure period, the rates of transmission between vaccinated and unvaccinated calves were directly assessed. The findings demonstrate that BCG provides 58 percent direct protection against infection, whilst offering a higher indirect efficacy of 74 percent by reducing transmission from vaccinated animals that still contract the disease. Combined, this delivers an estimated total efficacy of 89 percent. Incorporating these findings into an epidemiological model of the Ethiopian dairy sector demonstrates that routine cattle vaccination could significantly enhance prospects for eliminating bovine tuberculosis.
Bovine tuberculosis causes significant economic losses in livestock farming and poses health risks through zoonotic transmission. Quantifying the dual protective effects of the BCG vaccine, both in preventing initial infection and curbing onward transmission, confirms its effectiveness as a disease control tool. These findings provide essential evidence for agricultural policymakers and veterinarians seeking viable strategies to control or eliminate tuberculosis in dairy herds.
This research provides applied and tested evidence supporting the deployment of existing BCG vaccine formulations in veterinary medicine. Livestock producers, veterinary pharmaceutical distributors, and agricultural departments could adopt vaccination protocols to control bovine tuberculosis in dairy herds. Because BCG is already an established product, practical adoption relies primarily on veterinary regulatory approvals, field policy integration, and cold-chain supply planning rather than novel drug discovery, indicating a near-market application pathway.
AI-generated from the published abstract. Always read the original work before citing.
Bacillus Calmette-Guérin (BCG) is a routinely used vaccine for protecting children against <i>Mycobacterium tuberculosis</i> that comprises attenuated <i>Mycobacterium bovis</i>. BCG can also be used to protect livestock against <i>M. bovis</i>; however, its effectiveness has not been quantified for this use. We performed a natural transmission experiment to directly estimate the rate of transmission to and from vaccinated and unvaccinated calves over a 1-year exposure period. The results show a higher indirect efficacy of BCG to reduce transmission from vaccinated animals that subsequently become infected [74%; 95% credible interval (CrI): 46 to 98%] compared with direct protection against infection (58%; 95% CrI: 34 to 73%) and an estimated total efficacy of 89% (95% CrI: 74 to 96%). A mechanistic transmission model of bovine tuberculosis (bTB) spread within the Ethiopian dairy sector was developed and showed how the prospects for elimination may be enabled by routine BCG vaccination of cattle.
This page summarises published work. The authoritative version sits with the publisher.
DOI: 10.1126/science.adl3962
Is something wrong with this record? Report it or request removal.
Discussion
Have you built on this work, tried to replicate it, or seen it applied in practice? Share what you know. Verified researchers and MARATTO™ domain experts can open a discussion, and any member can reply. Contributions are reviewed before they appear.
No discussion yet. Open the first thread.
New to MARATTO™? Create a free account.
