The recent Ebola outbreak in the Democratic Republic of Congo (DRC) has once again brought attention to the urgent need for effective vaccines and treatments. With this being the 17th outbreak in the country since 1976, one might wonder why we are still struggling to find a solution.
The current outbreak is caused by the Bundibugyo strain, which has previously been associated with smaller outbreaks in the region. This strain, however, has not been the primary focus of vaccine development, as the more common Zaire strain has historically driven larger and more devastating outbreaks.
A vaccine called Ervebo, developed during the West Africa outbreak, has been approved and is available in several countries. But here's the catch: it targets the Zaire strain, not Bundibugyo. This raises a crucial question: why haven't we extended our efforts to cover other strains?
Dr. Anne Ancia, the WHO representative in the DRC, acknowledges that this is under consideration. However, the limited data on cross-protection and safety concerns surrounding the use of Ervebo for Bundibugyo are significant hurdles.
Dr. Thomas Geisbert, a researcher at the University of Texas Medical Branch, highlights an interesting study where a similar vaccine provided protection to monkeys against Bundibugyo. But he also points out the limitations of this data and the need for larger studies. The safety aspect is a major concern, and as Geisbert puts it, it's a tricky decision for clinicians.
The WHO's Dr. Sylvie Briand confirms that Ervebo is not their top choice due to the lack of evidence for cross-protection. Merck, the vaccine's manufacturer, has contributed to a global stockpile and is willing to produce more doses if needed.
The good news is that efforts are underway to develop vaccines specifically targeting Bundibugyo. An experimental vaccine using the same technology as Ervebo is showing promise, and a nonprofit group, IAVI, is prioritizing its development. Additionally, a vaccine using similar technology to the Oxford/AstraZeneca Covid-19 vaccine is in the works, although it may take a bit longer to ramp up production.
When it comes to therapeutics, there are some existing drugs that may provide hope. Antiviral drugs like remdesivir and monoclonal antibody cocktails are being considered. Dr. Amanda Rojek from Oxford's Pandemic Sciences Institute emphasizes the importance of broad-spectrum approaches that can work across multiple Ebola virus species.
The US government has historically been a major funder of trials during health emergencies, but support has waned under the Trump administration. However, BARDA and the National Institute of Allergy and Infectious Diseases have supported the development of Ervebo and antibody drugs.
Dr. Jean Kaseya, head of the Africa Centres for Disease Control and Prevention, expresses frustration at the lack of availability of medicines and vaccines. He believes that if the outbreak were in Europe or the US, resources would be more readily available.
Despite the challenges, Dr. Rojek argues that the world is in a better position now than it was in 2014. We have improved surveillance systems, faster diagnostics, and established trial protocols. While this outbreak presents unique challenges, it is not the same dire situation as in 2014.
In conclusion, while the development of vaccines and therapeutics is crucial, it's important to remember that outbreak control is not solely dependent on these tools. Rapid diagnosis, isolation, infection prevention, contact tracing, and community trust are equally vital components. As we continue to navigate this outbreak, let's hope that the ongoing efforts bear fruit and provide much-needed solutions.
