In as little as a few weeks, a promising experimental Canadian Ebola vaccine will be injected for the first time into healthy human volunteers.
The move to a phase 1 clinical trial is happening much more swiftly than the Iowa pharmaceutical company developing the vaccine imagined before Ebola began to ravage West Africa – and yet the shots still won’t make it to the front lines of the crisis until the beginning of 2015, at the earliest.
That waiting period is a stark reminder of how time-consuming and tricky it can be to prepare untested treatments or vaccines for safe use in the field during a public-health emergency such as the current Ebola outbreak, which the World Health Organization is now warning could infect as many as 20,000 people and last as long as nine months.
“When a crisis emerges, you don’t have either the time to devise a good protocol or the luxury to implement that protocol the way you would want to,” said Jonathan Kimmelman, a professor of biomedical ethics at McGill University. “There are going to be tremendous logistical challenges that are going to interact with the scientific value of the undertaking.”
In the case of the Canadian vaccine, known as VSV-EBOV, human trials are expected to begin this fall at the Walter Reed Army Institute of Research in Silver Spring, Md., according to the U.S. National Institute of Allergy and Infectious Diseases (NIAID), which is collaborating with the U.S. Department of Defence and NewLink Genetics Corp., the Iowa drug maker, on testing the vaccine in people.
The plan, according to NewLink, is to enroll somewhere between 25 and 75 healthy adult volunteers in a trial that would test whether the vaccine is safe and whether it produces an immune response that matches what researchers have observed in the non-human primates on which the vaccine has been tested.
Anthony Fauci, the director of NIAID, predicted Thursday that it would take until the end of this year to collect and analyze data from the phase 1 trial of the Canadian vaccine, and from a similar trial of a different vaccine NIAID is developing with pharmaceutical giant GlaxoSmithKline Inc.
That NIAID-GSK vaccine, based on a chimpanzee cold virus, begins trials in humans next week.
“When you’re dealing with normal human beings who are the recipients of the vaccine, safety is paramount,” Dr. Fauci said.
If the Canadian vaccine is deemed safe, who will get it? How will it be distributed? And how will researchers be able to determine how well it does or does not work?
Some of those questions should be answered Sept. 4 and 5, when more than 100 experts and pharmaceutical company representatives from around the world gather in Geneva for a WHO consultation on experimental therapies and vaccines for Ebola.
The meeting is expected to feature a roundup of where experimental Ebola treatments and vaccines are in the drug development pipeline, along with fresh recommendations from the same ethical panel – expanded to include more voices from Africa – that on Aug. 11 endorsed the use of experimental drugs in the current outbreak under certain conditions.
That decision prompted the Canadian government to offer 800 to 1,000 doses of the VSV-EBOV vaccine, which was developed in part at the National Microbiology Lab in Winnipeg.
Brian Wiley, vice-president of business development for NewLink Genetics, said Thursday the company is scrambling to ramp up production of the vaccine.
As many as 10,000 more doses could be ready by the end of this year, he said.
Marie-Paule Kieny, WHO assistant director-general for health systems and innovation, said that if the Canadian vaccine performs well in safety trials it would most likely be given to front-line health workers in West Africa who are accidentally exposed to the virus in a fashion likely to cause infection, such as a needle prick.
In tests on non-human primates, VSV-EBOV has been shown to provide some protection after exposure, much like the rabies vaccine.
“The reason why this is not currently targeting as a priority healthy people is because there is so little of it,” Dr. Kieny said. “Yes, 800 doses is better than 10 treatment courses of [the experimental treatment] ZMapp, for example, but still … think about the number of people who are involved in responding to this outbreak.”
Still, there is no guarantee the Canadian or the NIAID-GSK vaccine would be used primarily post-exposure.
Dr. Fauci, the NIAID director, said Thursday he expected the vaccines would be aimed at healthy people as a protective measure before exposure, not after.
Either way, the WHO needs to better understand any vaccine before it is injected into people at the chaotic centre of the outbreak.
Dr. Kieny pointed to the example of a German lab worker who was given VSV-EBOV in 2009, the only known instance of the vaccine being used on a human.
The worker recovered and it was never clear if she had Ebola, but she did develop a fever after receiving the vaccine, Dr. Kieny said.
Fever is one of the first signs of Ebola; workers on the front line would need to be able to distinguish between a fever caused by the vaccine and one caused by the disease.
“It’s very important when we bring these vaccines to very complicated environments like treatment centres, that there is knowledge of what the vaccine will induce,” Dr. Kieny said.