Fast-tracked Ebola vaccine

DW: You're heading what's been dubbed a fast-tracked human trial for a potential Ebola vaccine. What is the aim of this trial? What does it need to achieve or prove?

Adrian Hill: We're trying to do two things in this trial that has [just] started. We're looking at the safety of a new candidate vaccine for Ebola - a vaccine that is using really quite new technology - to ask, is it safe to use in people, and if it's safe, does it produce the sort of immunity that has been seen in experimental animals that were protected against Ebola. In other words, does it work as well in people as it has done in animals?

And you are using humans for this trial.

Well, of course we're using humans because there is an international public health emergency. There have been thousands of deaths from Ebola already in this outbreak in West Africa and it's not getting any better, in fact it seems to be getting worse. So we urgently need anything we can use to be honest to try and help control the outbreak, and a vaccine would be fantastic if we could produce this quickly.

But there has been some confusion over this trial already, and so it's worth making the point that there is no infectious Ebola involved - you're just trying to see whether you can produce an immune response.

Like most modern vaccines, we don't use the virus that we're trying to protect against, or the parasite to make the vaccine. We're using genetic engineering technology to take a gene from the Ebola - only one gene out of the many that it has - and we put that in using molecular techniques to a carrier. And that carrier vaccine allows us to then get the relevant bit of DNA into a cell.

And there the gene itself goes and makes a protein that is identical to the protein in Ebola. But the one protein from that virus can't give you the disease. So this is a fairly standard, modern way of generating a vaccine. But it means it's safe in the sense that you cannot get the disease from the vaccine.

And this is specifically for the Zaire strain of Ebola - so, specifically for the strain that we're seeing in this outbreak in West Africa?

That's what's unique about this trial today. There is a mixture formulation being tested in North America. We thought we'd prefer to take just the one strain that matches very well to the outbreak strain and test that as a vaccine here today for the first time. And our expectation is that is maybe more effective than using a mixture of strains, at least against the current outbreak.

So you're focusing on the efficacy for treating the situation right now.

Yes, exactly. So if you wanted to have a stockpile of a vaccine that would prevent against any Ebola strain, then you might go for the mixture. But since we know what the outbreak strain is, we know its entire gene sequence; we can tailor the vaccine to match that.

When we last spoke, you said that vaccine development takes time and money mainly for safety reasons. And as you've explained, these trials are safety trials. But the whole process is being fast-tracked with a possible view to having some doses of the vaccine used in the field as early as January 2015. Is it realistic or even scientifically wise to be pushing so fast?

I think it's a balance that one has to assess - and in this case, where people are dying in large numbers, the relevant governments and the WHO think a vaccine is a very high priority. There's been a lot of discussion about this. But the consensus is that if you're going to have a vaccine that is probably going to be safe, and we'll hopefully establish that over the next couple of months, and produces immunity that looks as if it would be useful, then it is reasonable to deploy that, and ask people whether they would like to have the vaccine, which is what is planed. I think it might even be earlier than January if things go well.

But the number of people being tested is relatively small, and really to test the safety you need trials on thousands of people, don't you?

To license a vaccine that we could say with great confidence, "We're going to give this to millions of people, and it's very unlikely there'll be serious problems," you need to do very large trials. That's not what we're discussing here. We're discussing an outbreak, where healthcare workers are at a high risk of infection and disease, and where - if we had a safe vaccine, even though it's only been tested in hundreds of people - we can provide an option for those people to choose to be vaccinated or not. And I think that is appropriate in the current setting after a lot of deliberation by people with a great deal of experience, both with vaccines and with outbreaks.

Adrian Hill is director of the Jenner Institute at Oxford University in the United Kingdom and an expert on vaccines. His team has been funded with a 3.5-million-euro grant from the Wellcome Trust, the Medical Research Council (MRC) and the UK Department for International Development (DFID) to start safety tests of the vaccine alongside similar trials in the US, which are run by the National Institute of Allergy and Infectious Diseases (NIAID, a part of the NIH).