EBOLA DRUG DISCOVERY
Vaccine designed in Canada has been 100 per cent effective in limited trials.
TORONTO — It appears the world finally has an effective Ebola vaccine.
A new study reported Friday that a vaccine designed by scientists working at Canada’s National Microbiology Laboratory in Winnipeg induces a quick and highly protective response against the virus.
This is the first time an experimental Ebola vaccine has been shown to protect people against the deadly disease. The former director of the Winnipeg lab, Dr. Frank Plummer, was ecstatic about the news.
“I think it’s fantastic. For the NML and the whole team that was involved in this, it’s the culmination of 15 years of work. It’s very, very exciting. Very, very gratifying,” said Plummer, who led the lab when the work was being done, but retired from that job last year.
“If proven effective, this is going to be a game-changer,” said Dr. Margaret Chan, director-general of the World Health Organization. “It will change the management of the current outbreak and future outbreaks.”
Further testing is necessary to see if the vaccine might also protect pregnant women, children and adolescents; those trials are already underway.
There had been high hopes this vaccine, called Rvsv -ZEBOV, would be effective. But in science, assumptions don’t count — data do.
And the data from this trial, conducted in Guinea, are persuasive, said Dr. Marie-Paule Kieny, a senior author of the trial and the World Health Organization’s point person for development of Ebola vaccines and drugs.
The vaccine protected 100 per cent of the people who received it. While experts caution that number will probably come down when the vaccine is used in more people, it’s a good result.
The findings were reported Friday in the medical journal The Lancet.
The study was meant to continue for a longer time, but an interim analysis conducted by the trial’s data and safety monitoring board concluded the vaccine was working.
The board of outside experts advised researchers to stop using a control group and offer vaccine going forward to all the people who met the criteria for the study.
The trial was conducted using what is called a ring vaccination design.
The idea behind ring vaccination is to create a buffer of protection around each case, so the virus cannot continue to spread.
When new cases of Ebola were diagnosed, the researchers offered to vaccinate people who had been in contact with the infected person, and the contacts of those contacts.
Some of the rings of people were vaccinated immediately. Others were told they would be vaccinated after a delay of three weeks. Researchers watched to see how many people in the two types of rings became infected.
In the first few days, there were infections in both rings. A vaccine takes time to kick start the immune system to protect against a new pathogen.
But after 10 days they saw no additional cases in the rings of vaccinated people. New cases continued to crop up in the rings of people who were randomly assigned to get vaccinated after the three-week delay.
Then the same pattern — a complete drop off in cases — was seen later when the people in the delayed rings were given the vaccine.