A hitherto unknown disease breaks out near the Ebola river in the country then known as Zaire, now the Democratic Republic of Congo (DRC).
asserted
disease → break → Congo
This was the first scientifically documented Ebola epidemic.
asserted
This → document → ?
Now, 50 years on, the DRC once again finds itself at the center of a major Ebola outbreak.
asserted
DRC → find → outbreak
The virus was identified in 2007 during an outbreak in Bundibugyo, Uganda.
asserted
virus → identify → Bundibugyo
Another outbreak occurred in the DRC in 2012.
asserted
outbreak → occur → 2012
Preparations could have been made for Bundibugyo
How can a virus that has been known for decades continue to infect thousands of people, yet there is still no licensed vaccine or official treatment?
uncertain
that → make → people
Torsten Feldt, a doctor of tropical medicine at Düsseldorf's University Hospital, sees this as a missed opportunity.
asserted
Feldt → see → opportunity
"We had come across the Bundibugyo virus in two previous outbreaks: 2007 in Uganda and 2012 in DR Congo.
asserted
We → come → Congo
So we had enough time to develop vaccines and therapeutic options.
asserted
we → have → vaccines
But we didn't make use of this opportunity, meaning crucial time was lost during the current outbreak," he said.
asserted
he → make → outbreak
Leonie Mayer from the German Center for Infection Research (DZIF) and the Institute for Infection Research and Vaccine Development at the University Medical Center in Hamburg-Eppendorf agrees.
asserted
Mayer → agree → Eppendorf
"They could of course have developed a vaccine and run pre-clinical trials before," Mayer told DW.
uncertain
Mayer → develop → DW
She stressed, however, that their effectiveness can only be assessed and confirmed during an actual outbreak.
asserted
effectiveness → stress → outbreak
Mayer is the lead author of a recently published study that examined whether Ervebo, an Ebola vaccine that has already been licensed, can be used against other types of Ebola as well.
asserted
that → publish → Ebola
From an immunological point of view, and compared to — for example — influenza or HIV, Ebola is a very worthwhile candidate for a vaccine.
asserted
Ebola → compare → vaccine
Influenza viruses are constantly mutating, and the human immunodeficiency virus is particularly good at evading our immune defenses.
asserted
virus → mutate → defenses
"I think — and perhaps it's kind of a blessing in disguise — that it will be relatively straightforward to develop a vaccine against Bundibugyo," said Mayer.
asserted
Mayer → think → Bundibugyo
Herein lies the paradox.
asserted
paradox → lie → ?
From a scientific point of view, Ebola is a good vaccine candidate, yet there is still no licensed form of prevention against the Bundibugyo variant that is currently circulating.
asserted
that → be → variant
Mayer explained that vaccines cannot be developed as a precautionary measure against every potential pathogen.
asserted
vaccines → explain → pathogen
Lack of funding or the prioritization of other pathogens often have a role to play.
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Lack → have → role
Many researchers had assumed that a fresh outbreak of the Sudan Ebola virus was more likely, and vaccine development for this strain is more advanced.
asserted
development → assume → strain
The known, highly dangerous orthoebolaviruses include Ebola virus (EBOV), previously called the Zaire Ebola virus (ZEBOV), the Sudan virus (SUDV), and the Bundibugyo virus (BDBV).
asserted
orthoebolaviruses → know → virus
The existing vaccine, Ervebo, was developed and licensed for use against the Zaire variant.
asserted
vaccine → exist → variant
This is why the existing Ebola vaccine has been of only limited use to people in the areas of the current outbreak.
asserted
vaccine → exist → outbreak
Another factor may also be relevant: The Bundibugyo virus appears to be less aggressive than the Zaire variant.
uncertain
virus → appear → variant
At first, that sounds like good news, but it may make it harder to contain, as people remain mobile for longer after being infected, and can pass on the virus without realizing.
uncertain
people → sound → virus
Ervebo vaccine shows immune response to Bundibugyo
asserted
vaccine → show → Bundibugyo
In the recently published study, Mayer's research team from the DZIF investigated whether the already licensed Ebola vaccine could trigger an immune response not only against EBOV, but against other types of Ebola as well.
uncertain
vaccine → publish → Ebola
They found cross-reactive T-cell responses against Bundibugyo, and also, to a lesser extent, against the Sudan virus.
asserted
They → find → virus
"We now know that the immune cells can most likely also recognize the Bundibugyo virus," she said.
asserted
she → know → virus
"Our data does not enable us to answer the question of whether this immune response actually provides protection, or if it results in a milder progression of the disease," she added, calling it an important gap in our knowledge.
asserted
she → enable → knowledge
Why can't existing vaccine be deployed yet?
asserted
vaccine → deploy → ?
If there's a vaccine that has already been licensed, and indications that it could protect people, why isn't it simply being deployed?
uncertain
it → be → people
Mayer explains the dilemma.
asserted
Mayer → explain → dilemma
For one thing, she said, it's not ethical to deploy a vaccine if you're not sure whether or how well it works.
asserted
it → say → vaccine
Also, if it were used on a large scale, it would no longer be possible to establish whether it actually works: A reduction in cases could also be a result of other measures, or the epidemic might already have passed its peak.
uncertain
epidemic → use → peak
Jürgen May, a specialist in tropical diseases at the Bernhard Nocht Institute, also warns against mass vaccination.
uncertain
May → warn → vaccination
"Mass vaccination without proof of efficacy could create a false sense of security, forfeit trust, and, if it does not provide sufficient protection, make study impossible," he said.
uncertain
he → create → protection
"If we inoculate people with a vaccine on a large scale, and afterwards it turns out that it was nothing like as effective as we expected, it's very difficult to communicate that to people on the ground," Mayer said.
asserted
Mayer → inoculate → ground
…and 20 more, not listed.
The Aporia
