FLICKR, NIAIDA Phase 1 trial in China has demonstrated the safety of a new Ebola vaccine and hinted at its efficacy, according to a study published today (March 25) in The Lancet. The vaccine candidate is the first to incorporate immunogens from the strain of Ebola that has terrorized West Africa for nearly a year; all other tested Ebola vaccines have been based on the strain that caused an outbreak in Zaire in 1976, according to a press release.
In the Phase 1 trial, investigators administered the new vaccine candidate, developed by the Beijing Institute of Biotechnology and Tianjin CanSino Biotechnology, or a placebo to 120 healthy Chinese adults. Four weeks later, all 40 participants who received a high dose of the vaccine showed a positive immune response, as did 38 out of 40 participants in the low-dose group. Those who had received the high dose produced more antibodies than those in the low-dose group. No serious adverse events were reported. The researchers plan to follow the vaccine recipients to assess long-term immune responses.
“This adenovirus type-5 Ebola vaccine vector is an example of how quickly existing vaccine platforms can be modified to incorporate a new virus strain, and moved, with minimum testing in animals, into trials in humans during a crisis situation,” Andrea Marzi from the National Institute of Allergy and Infectious Diseases and Darryl Falzarano from the University of Saskatchewan in Canada wrote in an accompanying commentary. “However . . . ultimately, the effectiveness of all these vaccines will only become clear when they proceed to phase 2 efficacy trials in outbreak regions.”
Meanwhile, an efficacy trial for another Ebola vaccine candidate, NewLink Genetics and Merck’s VSV-EBOV, began yesterday (March 25) in Guinea. The trial will use a “ring vaccination” strategy to target 10,000 people in contact with 190 Ebola patients over the next two months, Time reported. “We are committed to ending this epidemic,” Sakoba Keita, the national coordinator of the Ebola fight in Guinea, said in a World Health Organization statement. “Combined with control measures that we are putting in place with our partners, a safe and effective vaccine will allow us to close this trying chapter and start rebuilding our country.”