(Recast) Interview: Spanish doctor optimistic over tests on new Ebola vaccine

Doctors in the Carlos III Hospital in Madrid are on the verge of commencing the penultimate phase of clinical trials on a vaccine developed to combat the Ebola virus, which could be available for use within a year.

The vaccine, which has been jointly developed by the World Health Organization and Doctors Without Borders with the collaboration of several different nations such as Spain, has been successfully tested on animals similar to humans and 4,000 volunteers in Guinea.

Now it will also be tested on a series of Spanish volunteers, none of whom receive any payment for their efforts, other than the satisfaction of knowing their efforts could help to save thousands of lives in the future.

Doctor Martha Arsuaga, from the Carlos III Hospital explained to Xinhua how the tests would be carried out and also how the peculiarities of the Ebola virus could complicate their task.

She said that the vaccine had been made by "introducing an Ebola protein in another virus and we can see what antibodies are produced" and "how long after the introduction of the vaccine they are produced and what immunity they give."

This is the third stage of a development which has taken place over the last 12 months, and Dr Arsuaga expressed satisfaction that, working together investigators had needed such a short period to produce something "which usually takes 10 years," to develop.

"Now in less than a year we have developed a vaccine, which is very good and with very few side effects and which is efficient. It has been a challenge and an achievement," she said.

Ebola, explained the Doctor, is a complicated virus to combat because of its special characteristics.

"It's hard to make a vaccine because there are several types (of Ebola) and it is hard to make one which covers them all," she said, explaining that the vaccine was "made for the 'Zaire' type Ebola, which is which has the highest mortality and the highest number of outbreaks."

However, "if next year we are against the 'Sudan' version of the virus, we would have work to do, or if the Zaire type starts to mutate, (and it has mutated with a 30 percent variation since the start of the outbreak in Africa), we would have to modify the vaccine."

The forthcoming trials will see the vaccine tested on healthy people, who have had no previous exposure to the Ebola virus. The tests will see how many antibodies the test subjects are able to generate after being given the vaccine, these levels are them compared to those in the plasma of people who have recovered from Ebola.

"If they have developed enough antibodies, they are considered immune from the disease," said Dr Arsuaga.

The doctor explained that the level of antibodies in the volunteers would be evaluated over a year to ensure the level was maintained. However, she also said that although in the past immunity following a vaccination was considered to be for 10 years, in the case of hemorrhage fevers such as Ebola and yellow fever, it is now believed that immunity for someone who has either been vaccinated or recovered from the illness is for life.

If these tests are successful, trials will move on to phase 4, which "is for people who have been exposed to the virus, people who are ill and pregnant women to see if it works with them."

Studies also need to be carried out to see whether the vaccine would also work as a cure, rather than as merely a preventive measure and as such could be effectively administered after someone has been exposed to the virus, as happens in the case of the rabies vaccine, which is usually only given after someone has been bitten by a rabid animal.

However, Dr Arsuaga was optimistic that the vaccine will be ready to be distributed in "one or two years," adding that "if there was another Ebola outbreak, I'm sure we would use it now."

So are we on the verge of preventing one of the most moral viruses known to humanity? Endit