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Ebola: The race for drugs and vaccines Ebola: The race for drugs and vaccines
(2 months later)
The race is on to find a cure for the disease that has killed more than 5,000 people in West Africa. The race is on to find ways to prevent and cure the Ebola virus - a disease that has killed more than 8,000 people in Sierra Leone, Guinea and Liberia.
There are no proven treatments for people with the Ebola virus or vaccines to prevent infection in the first place. There are no proven treatments for Ebola or vaccines to prevent individuals becoming infected.
However, progress is now being made on an unprecedented scale.However, progress is now being made on an unprecedented scale.
Trials, which would normally take years and decades, are being fast-tracked on a timescale of weeks and months.Trials, which would normally take years and decades, are being fast-tracked on a timescale of weeks and months.
Vaccines in developmentVaccines in development
Vaccines train the immune systems of healthy people to fight off any future infection.Vaccines train the immune systems of healthy people to fight off any future infection.
Two Ebola vaccines have been rushed from promising animal studies into human trials. Three potential immunisations are frontrunners, having been rushed from promising animal studies into human trials.
One is produced by GlaxoSmithKline (GSK) and the National Institutes of Health in the US, and the other was designed by the Public Health Agency of Canada and is being produced by Merck. One is produced by GlaxoSmithKline (GSK) and the National Institutes of Health in the US, another is being developed by the Public Health Agency of Canada in collaboration with Merck.
GSK has inserted an Ebola gene into a weakened chimpanzee virus, which is unable to replicate in the human body. And the third to enter human testing is made by Johnson and Johnson together with the company Bavarian Nordic.
Initial tests on 20 volunteers in the US showed it was safe and that the tiny fragment of Ebola's genetic code was enough to generate an immune response. The plan is for the different vaccines to be tested in several trials across the three worst affected countries in the next few months.
Further trials are taking place in the UK, US, Switzerland and Mali to see if the immune response is strong enough to fight off an Ebola infection and how long any such protection would last. GSK's version uses a chimpanzee common cold virus to carry a single Ebola protein. The vaccine cannot trigger either disease but the hope is it will prompt the production of protective antibodies against Ebola.
The Canadian vaccine is based on adding an Ebola gene to a virus that normally infects livestock. Initial tests in 60 volunteers in the UK showed it was safe and that the tiny fragment of Ebola's genetic code was enough to generate an immune response - but scientists aren't sure yet whether this is strong enough to actually protect people from the disease.
It is being tested in the US and Switzerland, and there are plans for trials in Gabon and Kenya. The real test comes next as trials start in Liberia.
Initial safety results on 34 volunteers in Geneva are promising, according to Swiss scientists. They plan to carry out further checks to see whether the vaccine provokes an immune response before they publish their data in a scientific journal in 2015. This Liberian trial has three separate parts. Scientists hope to recruit 10,000 people to be given the GSK vaccine, 10,000 to receive the Merck jab and a further 10,000 to get a dummy, placebo vaccine.
Johnson and Johnson also has a vaccine in the pipeline, and the World Health Organization (WHO) is evaluating developments in Russia and Japan. Researchers will then see if any of the vaccines offers greater protection from the virus, by comparing the number of people who get the infection in all three groups.
The Merck vaccine that is planned to be tested in Liberia uses a livestock virus to carry a single Ebola gene.
Johnson and Johnson announced the start of their vaccine trial in January 2015. This uses a different approach - two separate jabs will be given in the hope the second one boosts the effectiveness of the first.
If this is proven safe and effective in initial tests, their is hope the trial will be moved to West Africa this year.
The World Health Organization (WHO) is also evaluating developments in Russia and Japan.
Vaccine challengesVaccine challenges
The first major issue is running the clinical trials at speed, nothing like this has been done before. Some experts now say, with Ebola cases going down in Sierra Leone, Guinea and Liberia, it will be harder still to prove whether a vaccine actually works.
Ethical issues surround testing a vaccine during an outbreak, and researchers face a lack of public trust in some communities And researchers will have rely on thousands of volunteers to test these as yet experimental jabs. In some communities, they will face mistrust.
When the trials move to the front line of the Ebola outbreak, then it will be healthcare staff and burial workers who will be immunised. There are also practical issues to take into account - some of the immunisations need to be kept at minus 80C in hot countries with limited access to electricity.
There are no plans for mass vaccination of the general population before June 2015, but the WHO has not ruled it out. But if all these obstacles are overcome and a vaccine is found to work, there is hope a jab could be more widely available towards the end of 2015.
There are also practical issues to address as both vaccines contains live, but weakened, virus. Questions will then be asked about who gets the vaccine first.
It means the shots will have to be kept below minus 80C in hot countries with limited access to electricity.
The drug companies also want indemnity in case something goes wrong when they are asked to rush through a vaccine.
Promising drugsPromising drugs
Drug research is also taking place at pace. Instead of preventing infection like vaccines, these are designed to boost the recovery of those who have been infected.Drug research is also taking place at pace. Instead of preventing infection like vaccines, these are designed to boost the recovery of those who have been infected.
The WHO says it is getting daily proposals for potential medicine, yet many show no activity against the virus.The WHO says it is getting daily proposals for potential medicine, yet many show no activity against the virus.
Two potential drugs are being tested at Medicins Sans Frontieres facilities.Two potential drugs are being tested at Medicins Sans Frontieres facilities.
They both interfere with the way viruses replicate inside our cells:They both interfere with the way viruses replicate inside our cells:
Trials are due to start in December, with the first results expected in February 2015.
Other drugs such as ZMapp have attracted attention during the outbreak.Other drugs such as ZMapp have attracted attention during the outbreak.
Two US aid workers and a Briton recovered after taking ZMapp, but a Liberian doctor and a Spanish priest died.Two US aid workers and a Briton recovered after taking ZMapp, but a Liberian doctor and a Spanish priest died.
Like all other drugs, there is a lack of clinical evidence about whether it does work and stocks have been extremely limited so trials have been hampered.Like all other drugs, there is a lack of clinical evidence about whether it does work and stocks have been extremely limited so trials have been hampered.
Ethical quandaryEthical quandary
Drugs trials are even more ethically controversial than vaccine trials in the midst of this outbreak.Drugs trials are even more ethically controversial than vaccine trials in the midst of this outbreak.
Should normal randomised clinical trials take place?Should normal randomised clinical trials take place?
It allows doctors to know for certain whether a drug is effective, but it means withholding a potentially life-saving treatment during a deadly outbreak.It allows doctors to know for certain whether a drug is effective, but it means withholding a potentially life-saving treatment during a deadly outbreak.
One option being used is to compare survival in the same centres before and after drugs were used.One option being used is to compare survival in the same centres before and after drugs were used.
Survivor's blood Survivors' blood
A different approach to manufacturing a drug is to harness one survivor's immune system to help another who is sick. A different approach is to harness one survivor's immune system to help another who is sick.
The body produces Ebola-fighting antibodies in response to an infection.The body produces Ebola-fighting antibodies in response to an infection.
So the idea is to purify the blood, extract the antibodies and give those to sick patients.So the idea is to purify the blood, extract the antibodies and give those to sick patients.
Studies on the 1995 outbreak of Ebola in Democratic Republic of Congo showed seven out of eight people survived after being given the therapy.Studies on the 1995 outbreak of Ebola in Democratic Republic of Congo showed seven out of eight people survived after being given the therapy.
This approach is being trialled in Guinea, led by the Antwerp Institute of Tropical Medicine.This approach is being trialled in Guinea, led by the Antwerp Institute of Tropical Medicine.