rVSV-ZEBOV is a recombinant, replication competent vesicular stomatitis virus-based candidate vaccine expressing a surface glycoprotein of Zaire Ebolavirus which was tested in preventing Ebola virus disease in contacts and contacts of contacts of recently confirmed cases in Guinea.
A commentary notes that although rVSV-ZEBOV seems to be highly efficacious and safe in the context of an outbreak, some questions remain. One that has not been adequately addressed is with regards to durability—is the vaccine long-lasting? Another question relates to improvements in safety-can the VSV-based Ebola virus vaccines, which appear to be the lead candidates for use in human beings, be further attenuated to reduce the number of adverse events noted in phase 1 trials without reducing efficacy? The commentator suggests that after 40 years, there now appears to be an effective vaccine for Ebola virus disease to build upon. This success, he notes has been achieved by leveraging findings from published preclinical studies to justify the use of the rVSV-ZEBOV vaccine during an outbreak without the need for time-consuming and costly good laboratory practices (GLP) or GLP-like preclinical studies required by regulatory policies.
Also published in the Lancet are data from a phase 2 trial of a recombinant adenovirus type-5 vector-based Ebola vaccine in healthy adults in Sierra Leone which reported that the vaccine was safe and highly immunogenic.