Source: The Conversation (Au and NZ)
When it comes to Ebola outbreaks, it’s not often we have two pieces of good news in one week.
First, we heard there’s new funding of up to US million to fast-track the development of vaccine candidates against the type of virus circulating in the Democratic Republic of the Congo (DRC) and neighbouring Uganda.
Then, we heard authorities had downgraded the confirmed numbers of Ebola deaths and cases in the region. As of June 2 local time, DRC health authorities reported 344 confirmed cases, including 60 confirmed related deaths. Uganda has reported 15 confirmed cases, including one death.
Previously, suspected cases in the region were more than 1,000. Here’s what we know about the three vaccine candidates announced this week and why we still have a long way to go before this concerning outbreak is under control.
Don’t we already have Ebola vaccines? Yes, we have two approved Ebola vaccines. One is Ervebo, the other Zabdeno/Mvabea. Both are effective and approved for protection against the Zaire Ebola virus specifically. However, this is a different virus to the one circulating in the DRC and Uganda currently, the Bundibugyo Ebola virus.
Unfortunately, different types of Ebola virus have different surface proteins that the vaccine targets. This means existing vaccines against the Zaire virus aren’t effective enough to be used against the Bundibugyo virus. The newly announced funding, from the Coalition for Epidemic Preparedness Innovations, aims to fast-track the development of the first, approved human vaccine specific to the Bundibugyo virus.
This support includes facilitating clinical trials as quickly as possible so if a vaccine proves both safe and effective it will be available as fast as possible. Here’s what we know about the three vaccine candidates.
1. IAVI vaccine A World Health Organization (WHO) expert panel called this “the most promising candidate vaccine”. It’s a single-dose vaccine that’s being developed by the International AIDS Vaccine Initiative (or IAVI) with the University of Texas Medical Branch.
It uses a similar approach to the approved Ervebo vaccine. The vaccine candidate has been tested in macaque monkeys, where it was shown to protect against the Bundibugyo virus. But it hasn’t yet been tested in humans.
The WHO expert panel said clinical trials were likely seven to nine months away. 2. Moderna vaccine This vaccine candidate is from the same United States-based pharmaceutical company that makes one of the approved COVID mRNA vaccines.
The company also has an approved mRNA vaccine against respiratory syncytial virus, or RSV. It’s developing an mRNA-based vaccine targeting the surface glycoprotein of the Bundibugyo virus. The company says the latest funding will support preclinical studies (meaning, animal or laboratory studies) and human clinical trials.
3. University of Oxford vaccine The third candidate is being developed by the University of Oxford and Serum Institute of India. It’s based on essentially the same technology used in the Oxford/AstraZeneca COVID vaccine.
The testing of this candidate is really just starting. And the WHO expert panel said extra animal data was needed. Yet it said this candidate vaccine could be in human clinical trials within two to three months.
If successful, the experts noted a single dose could be suitable for contacts of Ebola cases. However, for high-risk but unexposed populations, such as health-care workers and front-line responders, two doses might be considered. This group has already produced vaccines against another type of Ebola virus that has been tested in early phase human clinical trials.
Where to from here? There are many challenges in developing vaccines for diseases like Ebola. They need to be shown to be safe and effective, receive regulatory approval, manufactured at scale, then transported and delivered into people’s arms.
However, given some of the challenges with vaccine uptake and the negative perception and misinformation surrounding vaccination, it can be harder to recruit people to vaccine clinical trials. That’s especially for studies involving healthy volunteers, often conducted in countries far away from those affected.
The later phase clinical trials are typically conducted in the affected region. But these are often remote, have limited health care resources and may be in conflict zones. These make it even harder to conduct the types of clinical trials needed to show the vaccine candidates are safe and effective.
A vaccine would make a significant difference in our ability to control this outbreak. It would also be a useful tool for protecting against and responding to future outbreaks of the Bundibugyo virus. But until we have such a vaccine, basic infection control will still be the main way to control the current outbreak.
Paul Griffin in associated with the Immunisation Coalition and AMA Queensland.
He was the principal investigator on previous Ebola vaccine candidates.
Original source: https://analysis1.mil-osi.com/2026/06/04/three-new-ebola-vaccines-are-being-developed-an-infectious-disease-expert-explains/