In the first phase one trial based on the 2014 strain of the virus, a new Ebola vaccine has been found to be safe.
The experimental vaccine, developed by the Beijing Institute of Biotechnology and the Tianjin CanSino Biotechnology, also provokes an immune response in recipients, noted the study published in The Lancet
. Until now, all tested Ebola virus vaccines have been based on the virus strain from the Zaire outbreak in 1976.
"On the basis of our findings, we believe that the Ebola vaccine we assessed has some potential," said Fengcai Zhu, lead researcher from the Jiangsu Provincial Center for Disease Prevention and Control in China. "A significant advantage of this type of vaccine is that stable and much easier to store or transport in tropical areas with inadequate cold-chain capacity, such as Africa," Zhu added.
The researchers tested the safety and immunogenicity of a novel Ebola vaccine, based on the 2014 Zaire Guinea Ebola strain, and delivered by a virus-like structure (known as a recombinant adenovirus type-5 vaccine).
For the trial, 120 healthy Chinese adults were randomly assigned in equal numbers to receive placebo, a low dose, or high dose of the vaccine. The randomised trial took place at one site in Taizhou County, Jiangsu Province, China.
The researchers found that 28 days after vaccination, 38 out of 40 participants in the low-dose group and all 40 of those in the high-dose group had a positive immune response to the vaccine, with participants in the high-dose group producing higher quantities of antibodies than those in the low-dose group.
No specific immune response was recorded in the placebo group. However, the researchers noted that the study does not show whether the level of immune response observed might ultimately be able to offer protection against Ebola virus.
"Whether this candidate vaccine could become a final vaccine for widespread use against Ebola outbreaks is still uncertain, because of the issues of HIV-1 acquisition rates and the pre-existing immunity, especially in west Africa," Zhu noted. More evidence from clinical trials is needed about these concerns, Zhu added.