Post WHO’s approval, Merck’s Ebola vaccine raises hopes for fresh approach

New Delhi: In May 2018, the World Health Organization (WHO) announced its support for the use of rVSV-ZEBOV, an experimental Ebola vaccine developed by Merck & Co., in the Democratic Republic of Congo (DRC) to help stop the spread of Ebola. The success of rVSV-ZEBOV and its ring vaccination approach to preventing the spread of Ebola will be critical to the future development of vaccines targeted for these types of infectious diseases, says GlobalData, a leading data and analytics company.

Merck’s rVSV-ZEBOV, which provides protection from the Zaire strain of Ebola, is being deployed using a ring vaccination approach where the people who are most likely to be infected receive vaccinations, specifically for at least two degrees of contact for people with confirmed Ebola cases.

Gilbert Saint Jean, PhD, Pharma Analyst at GlobalData comments: “This includes vaccinations for high-risk groups known to be at increased risk for exposure to Ebola. Community health workers, laboratory workers, surveillance team members, and burial workers are considered part of this high-risk group. Ring vaccination as an immunization strategy is not unprecedented, as it was applied during the final years of the smallpox eradication campaign.

“GlobalData views the deployment of rVSV-ZEBOV as a potential landmark case study for how to efficiently evaluate an investigational vaccine’s ability to protect against low incidence, outbreak-prone diseases, as compared with the traditional randomized controlled trial (RCT).”

Currently, there are an increasing number of Ebola vaccine products in the R&D pipeline. GlaxoSmithKline (GSK) is developing a bivalent Ebola vaccine that provides protection for the Sudan and Zaire viral strains. Janssen, the pharmaceutical division of Johnson & Johnson (J&J), is developing vaccines for protection against the Sudan and Zaire strains of Ebola virus, as well as the related Marburg virus.

Public-private partnerships have been essential to the advancement of Ebola vaccines. For example, Merck & Co.’s vaccine was originally developed by Canadian government laboratories before it was licensed to NewLink Genetics, which then licensed it to Merck. The US National Institutes of Health has been involved in the development of GSK’s, Janssen’s, and Merck’s Ebola vaccines, and China and Russia have also supported Ebola vaccine development.

Saint Jean adds: “While there have been promising advances in Ebola vaccine development in recent years, difficult ethical dilemmas—which are being partially circumvented by alternatives to RCTs—will require creative human clinical trial approaches for determining vaccine efficacy. This impetus resulted in the ring vaccination approach that was applied in Guinea, during the 2013–2016 Ebola epidemic, and is currently being applied in the DRC. The success of this study will have far-reaching implications for the vaccine R&D community.”