Scientists at the University of Oxford have developed a new vaccine to tackle Ebola, and the UK regulator has given permission for clinical trials to take place.
There's still no treatments or vaccines for this Ebola outbreak, and containment really relies on contact tracing and being able to isolate and treat those who are diagnosed with Ebola.
And the Bundibugyo Ebola virus is actually about 35% different in its genome compared to the Zaire and Sudan viruses.
Nevertheless, is this going to be fast enough, at the rate at which this Ebola outbreak is progressing?
That particular outbreak still saw vaccine studies as well as treatment studies that were executed during the outbreak.
Scientists at the University of Oxford have developed a new vaccine to tackle Ebola, and the UK regulator has given permission for clinical trials to take place. The researchers began developing the vaccine in May, when a public health emergency was declared in the Democratic Republic of Congo. The driver for the initiative is that the outbreak there is caused by a different form of Ebola virus, which is not catered for by our existing vaccines, so we needed to make a new one, which the Oxford team have managed to do in record time. Boghuma Titanji is an infectious diseases specialist and virologist at Emory University. Chris Smith asked her to bring us up to speed…
Boghuma - The Ebola outbreak is still continuing with more cases being recorded, and right now we have had over 2,000 confirmed cases and over 700 deaths. There have also been cases in neighbouring Uganda, so far 20 cases, all of them with links to importation from the DRC across borders, and so far with the Uganda outbreak, there have been two deaths. There's still no treatments or vaccines for this Ebola outbreak, and containment really relies on contact tracing and being able to isolate and treat those who are diagnosed with Ebola.
Chris - This is because it is a different strain of Ebola than the one that caused the biggie about 10 years ago.
Boghuma - That is absolutely correct. So the strain of Ebola virus that is causing the current outbreak is the Bundibugyo Ebola virus strain, and it is actually one of the four strains that have been known to cause a disease in humans. However, as opposed to the Zaire Ebola virus that has caused a majority of previous outbreaks, this current virus has only ever caused two previous outbreaks prior to the ongoing outbreak in the DRC and in Uganda. So while it is an Ebola virus, we don't have quite as much experience with it, and we also do not have as many vaccines, or we don't have any vaccines for it, or any treatments that have been proven to be effective against this particular Ebola virus.
Chris - And is that because, although they're a big family of, or a family of Ebola viruses, the individual members like this one, the Zaire strain, they're sufficiently different to each other that it won't work? Like we can use, say, the vaccine against smallpox also protects against the monkeypox virus. It's not going to work like that necessarily. So we need a bespoke vaccine for this variant.
Boghuma - Because the family of viruses is one large family of viruses, people often assume that we would have one vaccine that is capable of effectively protecting against the four Ebola species that cause human disease. But, like you have mentioned, these viruses are quite different in their genetic makeup. And the Bundibugyo Ebola virus is actually about 35% different in its genome compared to the Zaire and Sudan viruses. And that difference is enough to actually make it be a completely different species, which means that if you were to develop a vaccine for it, you would have to develop a specific vaccine that targeted that virus.
Chris - So what have the Oxford team done that might get us over that hurdle?
Boghuma - The Oxford team has actually leveraged the platform that they used for the COVID vaccine, that is based on something called the chimp adenovirus, which is a benign virus that doesn't cause disease, but it's actually used as a carrier virus to be able to carry the protein target of the Bundibugyo virus and deliver it in the form of a vaccine, so that your body can generate an immune response to it that would hopefully be protective. And the reason why they've been able to do this is because they already had an existing platform that has been demonstrated to be capable to deliver a vaccine effectively. So essentially, they've just swapped out the target and replaced it with the protein target of the Bundibugyo virus.
Chris - And how will they test it?
Boghuma - They're currently underway an approved phase one study, and phase one studies are really focused on demonstrating that the vaccine is safe and that it can stimulate an immune response. So that is the very base entry level of assessing whether a vaccine can then progress to additional studies to check whether it's actually protective. And the goal will be to assess whether this vaccine is safe and well tolerated in humans. And the second goal will be to assess whether it generates an immune response. The Serum Institute of India has already pre-stocked and produced about 620,000 doses of the vaccine preemptively, and 4000 of these doses have been donated for clinical studies.
Chris - Ah, right. So they're not waiting for the green light on the safety trials to actually make the stockpiles. They're racing ahead so that as soon as the green light comes on, and we've gone through safety trials, they're ready to go. So that should minimise the delays. Nevertheless, is this going to be fast enough, at the rate at which this Ebola outbreak is progressing?
Boghuma - It is very difficult to tell how quickly we will be able to get these vaccines into phase three studies, which are the actual studies that are meant to assess whether the vaccine itself generates a protective effect and can actually prevent people from acquiring Bundibugyo Ebola virus, because there are regulatory requirements within the countries where these vaccines will need to be rolled out. And sometimes these regulatory processes can take several months. However, I think it's very encouraging to note that we're just 57 days since this outbreak was identified, and we're already rapidly moving into a phase one study, which then sets the scene and the stage for moving into a phase two study, if the phase one studies are shown to be positive, and the vaccine is shown to be safe.
Chris - Is there the right resource on the ground to do this though? Because there's a reason why we've got this problem in the DRC, and it's been as bad as it has, which is there's been conflict, there's been political instability, and we know these are one of the worst provoking factors to drive public health disasters. You need a good public health system to get vaccines on the ground and into people at risk. So, is that actually going to really frustrate things? We can have all the vaccines in the world and if the politics isn't there, we're still no further along the track.
Boghuma - Well, the challenges that you mentioned are very real regarding the landscape where this Ebola outbreak is unfolding, with the mass displacements of people related to conflict and the multiple rebel groups operating in the area, as well as the limited public health infrastructure. But we must remember that in the 2018 to 2020 Zaire Ebola outbreak in the DRC, that also occurred in a very difficult to navigate part of the country. That particular outbreak still saw vaccine studies as well as treatment studies that were executed during the outbreak. And actually, the existing vaccines for Ebola Zaire were utilised in the context of this 2018 to 2020 outbreak, to effectively help with containing that outbreak.
