VOA常速英语:Ebola Vaccine Enters Final Trial Phase

An Ebola vaccine candidate enters the final phase of its trial Saturday (3/7) in Guinea. If successful, a vaccine could be ready for use in five or six months.

The VSV-EBOV vaccine was developed by Canada’s Public Health Agency. World Health Organization vaccine expert Dr. Marie-Pierre Préziosi said Phase III will be conducted in the Basse Guinée region. It’s had the highest number of Ebola cases in the country

“Phase III trial aims to test for safety and efficacy or effectiveness of a candidate vaccine. This is a final trial prior to licensure of a vaccine. The vaccination phase in itself is anticipated to last about 60 days. And then there will be a follow-up period of about 84 days. That is about three months. So altogether it should be around six months duration,” she said.

The vaccine is based on a genetically engineered virus that’s been given some proteins of the Ebola virus.

“This is a very common technique to make good vaccines,” she said.

The strategy being used in the Phase III trial is known as “ring vaccination.” It’s a technique that was used to eradicate smallpox in the 1970s. Researchers identify a newly diagnosed Ebola patient, who is called the “index case.” Then they trace all of his or her contacts and vaccinate them, if they give their consent. The goal is to create a buffer zone that prevents the spread of the disease.

Dr. Préziosi said it’s important to have an Ebola vaccine even though the number of new cases is on the decline.

“Although we see that cases are declining and the outbreak seems to be waning, unfortunately, as we speak there are still cases in various locations in Guinea. So, this really tells us that the epidemic is not over. We need to continue because this environment is quite uNPRedictable and the epidemic might flare-up again. And also if we are able to have an effective vaccine it would be really an invaluable tool to fight this outbreak and any other outbreak that would come in the future.”

She said a vaccine could be used in several ways in the next Ebola outbreak. For example, it could be given only to frontline workers – those in direct contact with patients – or given to large portions of a country’s population.

“We are all holding our breath because we are living a very important moment for this outbreak and for any future outbreak,” she said.

It’s not clear what the cost of an Ebola vaccine dose will be.