Three vaccines in development to curb the spread of Ebola

Three new vaccines are being developed to combat the rare strain of Ebola, which has already killed nearly 250 people. The International AIDS Vaccine Initiative (IAVI), which is working on a vaccine, said the outbreak risks becoming more severe than ever. The University of Oxford and the pharmaceutical company Moderna are also pursuing vaccines against the Bundibugyo strain. The Coalition for Epidemic Preparedness Innovations (CEPI), which is funding each group, said “every day counts.”

There are currently more than 1,000 suspected cases in the Democratic Republic of Congo, with nine confirmed cases in neighboring Uganda.

There is growing concern that this outbreak, which was only discovered after it had spread to a conflict zone with limited health resources, could reach the proportions of the largest Ebola outbreak in West Africa in 2014–2016. At that time, nearly 29,000 people were infected and more than 11,000 died.

Dr. Mark Feinberg, head of IAVI, said: “I think it’s showing that it’s going to be an outbreak as severe as that, if not worse, and developing a vaccine and other countermeasures is clearly a priority.”

This reflects the concerns of the medical humanitarian organization Médecins Sans Frontières (MSF), which said the situation is "deeply alarming" and that never before "have so many cases been recorded" so quickly.

Vaccines need to be developed for each variant of Ebola; there are six, but only three are known to cause epidemic outbreaks.

There is a vaccine for the most common species, Zaire, but this outbreak is being caused by another species, called Bundibugyo. It has only been seen twice before and does not have an approved vaccine.

IAVI is working on a modified version of the Ebola Zaire vaccine to combat Bundibugyo. The experimental vaccine has been tested in monkeys, where it quickly trained the immune system and provided almost 100% protection.

It will take seven to nine months to prepare the vaccine for clinical trials, although there are efforts to accelerate the timelines.

Meanwhile, pharmaceutical company Moderna has announced that it is using its mRNA technology - which was used to rapidly develop vaccines during the Covid pandemic - to work on Bundibugyo.

The University of Oxford has also stated that it is working on its own vaccine, which also saved lives during Covid, to develop a new vaccine against Ebola.

This is expected to be ready for clinical trials within two to three months.

Each vaccine aims to teach the body to recognize the same structure on the surface of the virus, known as the Bundibugyo glycoprotein. However, each uses different technologies to achieve this.

IAVI uses a live, but harmless, virus that has been engineered to also contain the Ebola glycoprotein. The immune system fights the harmless virus and in the process learns to fight Ebola.

The mRNA vaccine and the Oxford vaccine both send a piece of genetic code into the body. Once inside, it instructs the body to build the Bundibugyo glycoprotein, which the body recognizes as foreign and begins to attack.

All of this would give the immune system an advantage when facing a real Ebola infection.

However, changes in technology and the way they train the immune system could affect the level of protection or the number of doses needed. All of this needs to be tested in clinical trials./BBC