Vesicular stomatitis virus (VSV) can cause severe disease in cattle and other livestock but is not a threat to people. For about a decade, scientists have used VSV as an experimental vaccine delivery system against infectious diseases, including Ebola, Marburg, and Lassa fever viruses—but could people inoculated with those vaccines become a threat to transmit VSV to livestock?
Human clinical trials of a VSV-based Ebola vaccine are under way in Africa, Europe, and the United States. To evaluate the safety of the vaccine for secondary livestock transmission, NIAID researchers inoculated three different groups of pigs with either the VSV investigational Ebola vaccine, wild type VSV, or a nutrient used as a control. Then at regular intervals for up to 21 days, the researchers collected samples from different body locations and drew blood to test for virus and viral antibodies.
Their results, published in Emerging Infectious Diseases, show that although the VSV investigational Ebola vaccine replicates in inoculated pigs, there is no observable disease and minimal virus shedding—making transmission from humans to livestock unlikely.
de Wit E et al. Safety of recombinant VSV Ebola virus vaccine vector in pigs. Emerging Infectious Diseases. DOI: 10.3201/eid2104.142012 (2015).