As Uganda’s Ebola outbreak continues to claim lives the need for a vaccine grows greater. The outbreak was announced in September 2022, since which at least 28 deaths have been reported, with more suspected. Despite Uganda’s quick and efficient response, the international community is calling for accelerated research into vaccines against the ‘Sudan’ iteration of the virus. In October 2022, Science reported that Merck, the “pharmaceutical giant”, might be able to contribute to this.  

Science investigates 

The report suggests that “repeated inquiries” were needed to confirm the information. Conflicting insights were exchanged, during which time it was initially suggested that the vials had expired and been destroyed. However, eventually Merck “acknowledged” that it has “up to 100,000 doses” of an experimental vaccine. Frozen in Pennsylvania, the vaccine doses target the Sudan ebolavirus. According to Science the vaccine was developed in 2015 and 2016, following success with a Zaire ebolavirus candidate. It was frozen and not tested on humans but has been shown effective in monkeys.  

Dr Mark Feinberg led the Zaire Ebola vaccine programme at Merck. He described this discovery as “amazingly good news”. Dr Feinberg is now President and CEO of IAVI, which is also developing a Sudan ebolavirus candidate.  

Merck’s vaccine enters the scene  

Dr Nicole Lurie of CEPI indicated that the “potential availability” of this vaccine is “potentially game changing”. It comprises the gene for the surface protein of the Sudan ebolavirus, incorporated into vesicular stomatitis virus (VSV). Other developers of a Sudan Ebola vaccine include the Sabin Institute and the University of Oxford. However, there is now a “wildcard”, says Dr Lurie. This might be the most promising candidate, according to scientists who addressed Science. VSV vaccines have demonstrated “more robust and durable protection” than chimp adenoviruses.  

We look forward to hearing more from Merck on the subject of Ebola at the World Vaccine Congress in Washington 2023. To get your tickets click here.