I’ve chosen the light-hearted topic of Ebola to tackle next, so I’m afraid this post isn’t going to be full of laughs, but yesterday saw the announcement of some incredibly important news. A vaccine for Ebola may well have been found.
Even though I read the news and think I’m keeping myself up to date in a ‘well I read the Guardian so obviously I know what’s going on’ sort of way, if I actually tried to give an account of the Ebola crisis to somebody else, it would be along the lines of ‘there’s an Ebola outbreak in West Africa and it’s incredibly contagious and they are trying to contain it by trialling vaccines’. That’s pretty much it and nobody’s going to be offering me a Pulitzer prize anytime soon.
But – and yes I did read this in the Guardian – one of the Ebola vaccines being trialled in Guinea has been 100% successful, which may finally control the outbreak that has been killing thousands for the past year and a half. This is incredible news obviously for those affected in Liberia, Sierra Leone and Guinea, but it’s also exciting news for science. Until now there hasn’t been a vaccine approved for clinical use. When a vaccine can take 10-15 years to develop, that this was managed in one year is deeply impressive.
So, I wanted to take a look at the whole situation, from what Ebola is to why the epidemic began and why this news is going to have such a huge impact.
Background of Ebola
Ebola is a terrifying disease. Caused by a virus thought to have originally been carried by fruit bats, there is a 50% mortality rate, with victims dying of organ failure and haemorrhaging.
The disease was first identified in 1976 after two simultaneous outbreaks in Nzara, South Sudan and Yambuku, Democratic Republic of the Congo (known as Zaire at the time). The virologist Peter Piot, who is now famous for his work on Ebola and AIDS, wrote a fascinating article here (Part 1 and Part 2). To sum up, Yambuku is a village near the Ebola river and samples from there were sent to a lab in Belgium inside a plastic thermos flask. By the time the samples had gotten there, they were half melted and one of the test tubes had broken. With nobody knowing just how incredibly dangerous the virus was, tests were undertaken without special safety protocols until eventually they worked it out that the material they were working with was highly lethal. By going back to the village, Ebola’s transmission through bodily fluids was identified. The virus was named after the river Ebola so Yambuku itself wouldn’t become stigmatized, even though the river isn’t connected to the virus or its transmission.
These two outbreaks resulted in over 400 deaths, and between then and the end of 2013 there were 25 small outbreaks, all of which were contained. However, last year saw Ebola for the first time become an epidemic, which has so far resulted in over 11,000 deaths.So what happened this time which caused such a massive surge in the disease?
West Africa Ebola epidemic
For a magnified version of the timeline, click here.
The first report came from Guinea in December 2013, with more cases then appearing in Liberia, Nigeria, Senegal, and Sierra Leone. The World Health Organisation declared the epidemic to be a public health emergency of international concern on 8 August 2014. Since then the majority of outbreaks have been in Liberia, Sierra Leone and Guinea.
In a paper published in The New England Journal of Medicine, the WHO Ebola Response Team wrote that ‘the clinical course of infection and the transmissibility of the virus are similar to those in previous EVD outbreaks’, so it isn’t that the virus has suddenly mutated into an even more dangerous form. Previous outbreaks, they say, were ‘limited in size and geographic spread, typically affecting one to a few hundred persons, mostly in remote forested areas’. The reason Ebola has reached epidemic levels this time is because ‘the populations of Guinea, Liberia, and Sierra Leone are highly interconnected, with much cross-border traffic at the epicenter and relatively easy connections by road between rural towns and villages and between densely populated national capitals’.
It is control of infected people and who they have been in contact with, along with reporting of cases and the lack of drugs and vaccines which have led to it rapidly becoming a problem that was crossing country boundaries. West Africa has also never suffered from an Ebola outbreak before, with previous cases since the 1970s occurring in equatorial Africa, so the region was poorly equipped to formulate a response. The disease also hit urban areas and densely populated slums in some of the poorest countries in the world, whose civil war-damaged health infrastructures couldn’t handle the load. Funeral and burial practices have also been driving the spread of the disease, such as sleeping near an infected corpse for several nights, with 60% of Guinea’s cases and a staggering 80% of Sierra Leone’s cases linked to these practices.
Managing the outbreak
There have been two aspects to trying to control Ebola in West Africa – isolating infected people and trying to modify people’s behaviour. This isn’t just a case of flying in doctors, it’s also the information given out and how to manage deeply held cultural beliefs.
Fear has been a major barrier to overcome, leading people to hide infected family members and in some cases attack aid workers, which isn’t surprising when people who are treating you look like this. There is also a huge stigma around being infected, and, says the WHO: ‘The fact that no effective medical treatment exists has enforced the desire of families to care for patients in their homes or turn to traditional healers’, which leads me back to the announcement of the success of Merck’s Ebola vaccine.
Ebola vaccine
Several potential vaccines and drugs have been trialled during the epidemic, but this is the first that has generated so much excitement. The trial has been so successful that it’s now going to be given to all people at risk. The way it was tested is also interesting – using a ‘ring’ approach where those in contact with an infected person are vaccinated, rather than using a mass vaccination; the same method which was used to eradicate smallpox in the 1960s and ‘70s.
What’s next?
More evidence is required to show that the vaccine can protect populations through herd immunity, but randomization in the trial was stopped on 26 July so now all possibly infected people can receive it. The reason why I focused on Ebola is really the sheer impact that this work is going to have on how to manage infectious disease in the future. There are lessons to be learned from this epidemic, with there being a need for a global warning and response system for outbreaks, faster deployment of trained personnel and a change in guidelines about using drugs that work on similar viruses.
Overall, this is a global issue – who knows what the next outbreak of disease will be – but this positive news is definitely something to focus on.
Hypervelocity Science 
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