Ebola Outbreak in Africa Hampered by Lack of Resources, No Approved Vaccine

Health authorities are trying to contain an Ebola outbreak in Africa, but a lack of resources and no approved vaccine for the strain are hampering efforts.

The outbreak — with more than 130 people dead in the Democratic Republic of Congo — is already the third largest in more than a decade.

Since Ebola was first identified in 1976, outbreaks have occurred every few years, with West and Central Africa particular hot spots.

But the latest outbreak is caused by a strain of virus not seen since 2012.

On Sunday, the World Health Organization (WHO) declared the Ebola outbreak a public health emergency of international concern, with researchers hoping this will spur the world into action.

So what do we know so far about this outbreak?

What is the Bundibugyo virus?

Bundibugyo is one of five strains of virus that cause Ebola disease.

The viruses can move from animal hosts to humans, similar to the lyssavirus or Hendra virus in Australia.

People who are sick with Ebola initially develop flu-like symptoms that develop into severe vomiting, diarrhoea and unexplained bleeding at later stages.

The most common strain of virus, known as EBOV (Zaire), is responsible for most of the 25 or so outbreaks in the past 50 years.

Because it is the most frequent, it is the most studied, and has effective vaccines.

Until now, Bundibugyo has caused only two outbreaks, in 2007 and 2012.

Unlike EBOV/Zaire, there are no vaccines or treatments for this or other strains that have caused outbreaks in the past, Paul Griffin, director of infectious diseases at Mater Health Services, said.

"So for Zaire, which is the one that historically caused the largest and most frequent outbreaks, there are actually two options for vaccines," Professor Griffin said.

"For the other types, unfortunately, we don't have a vaccine available yet."

Dr Griffin said Ebola viruses could cause a very severe illness, and therefore have a high mortality, but they were not as easy to transmit as other diseases.

"The particular [strain] of Ebola we're talking about now has a quoted mortality of 25 to 50 per cent, but it does require very close contact and exposure to blood and body fluids to be transmitted," he said.

"It doesn't have the potential to be the next pandemic."

How does it compare to previous Ebola outbreaks?

The largest Ebola outbreak was the 2013–2016 West African epidemic, where almost 30,000 cases were recorded, and more than 10,000 people died.

Another outbreak occurred in 2018–2020 in Central Africa, where almost 3,500 cases were reported.

These were both caused by the EBOV/Zaire virus, and often in countries that had been affected by war.

The WHO suggested that many of the reported numbers were likely large underestimates.

This outbreak has had more than 510 suspected cases since the first case was reported at the beginning of May.

Getting concrete numbers on the ground in the region is particularly difficult, Professor Griffin said.

"My understanding is there's only been a very small number of people actually tested so far," he said.

"Poor health care resources and … other issues like conflicts and political unrest, it does make it very hard to institute the appropriate measures."

Why can't we use the existing vaccines?

During the 2013–2016 epidemic, a vaccine in development was fast-tracked and used to try to control the outbreak caused by the EBOV/Zaire strain, particularly in health care workers.

Hundreds of thousands of those vaccines are currently stockpiled for future Ebola outbreaks, but they are only confirmed to work for Ebola caused by the EBOV/Zaire strain.

Professor Griffin explained that this is due to the vaccine targeting surface proteins on the virus, and these are "quite different" between the different types of Ebola viruses.

Despite being first discovered in 2007, the Bundibugyo virus has occurred less often than the EBOV/Zaire strain and caused much smaller outbreaks

The first outbreak had 131 reported cases, and the second was 38 cases.

According to Professor Griffin, these smaller outbreaks likely meant that creating a vaccine was not seen as a high priority for funding.

"It's challenging with prioritising vaccine development. You look at a disease that obviously has such a high mortality, but … hasn't caused a lot of disease," he said.

"We see that with a lot of other very rare viruses. There's just not the resourcing, unfortunately, to be able to invest the time and effort, to be able to make a vaccine."

While there has been some early research in primates, which suggests the existing vaccine may provide some protection against the other Ebola strains, it's too early to tell if this will translate to humans.

That leaves treatment and containment as the tools to stem the tide of the current outbreak.

How will the WHO declaration help?

Because outbreaks of this strain have been rare and reporting data is limited, it is unclear how lethal the latest outbreak will be.

According to Professor Griffin, while there is no direct treatment available for this strain of Ebola, there are still options for the best care.

"Mortality also depends on what can be done as simple supportive care," he said.

"And while the mortality figures are quoted as very high over a long period of time, a lot of those cases didn't have access to even basic interventions like intravenous fluids.

"Best supportive medical care is likely to make a very significant difference, but unfortunately, that's rarely available."

According to Emma Thompson, the director of the MRC–University of Glasgow Centre for Virus Research in the UK, the outbreak highlights "a persistent weakness in epidemic preparedness".

"We tend to build tools around the best-known outbreak pathogens, but rarer viruses such as Bundibugyo virus can still cause severe disease and international spread," she said in a statement.

She suggested that contact tracing, genomic sequencing, and treatment centres that provided high-quality care would help limit infections and, therefore, deaths.

Because the WHO declared this a public health emergency of international concern, Professor Griffin suggested more resources might now be available to help limit the spread.

"The reason … is not because there's risk to other countries necessarily, but because of the gravity of the situation locally and the additional challenges faced by that region to try and contain [the outbreak].

"And hopefully this declaration might enable at least some better supportive care to be able to be provided to cases in this area."

How fast could we develop a new vaccine?

If this outbreak continues to worsen and requires the development of a vaccine, Professor Griffin said that assembling one at speed might be easier than it used to be.

"With advances we've seen in vaccine technology, partly accelerated by COVID, in theory we have the ability to make vaccines for new and emerging pathogens, or outbreaks of existing pathogens, much more rapidly than we may have in the past."

However, he noted international funding cuts and vaccine hesitancy might slow efforts.