A novel vaccine temporarily shielded lab monkeys from Ebola, and a booster jab provided lasting protection, according to a study that has endorsed approval for tests on humans.
A single shot of the vaccine, based on a cold virus that affects chimps, gave macaques "complete short-term and partial long-term protection" from the deadly virus, researchers reported in the journal Nature Medicine on Sunday.
Animals that received a booster shot developed "durable" immunity.
The US National Institute of Allergy and Infectious Diseases (NIAID) announced on August 28 that human testing would start in early September following the promising results in monkeys.
The results of the trials are expected by year's end.
If approved, "this vaccine will be beneficial for populations at acute risk during natural outbreaks or others with a potential risk of occupational exposure", said the study's authors.
They claimed to be the first to demonstrate a vaccine with "durable protection" against Zaire ebolavirus, which has killed 1841 of the 3685 people infected in Guinea, Liberia and Sierra Leone, according to World Health Organisation (WHO) numbers.
Nigeria has had another 21 cases and seven deaths from the haemorrhagic fever against which no licenced vaccine or treatment exists.
The early trials in humans are the first phase in a three-step vetting process.
They will be carried out among healthy adults not infected with the Ebola virus to determine if it is safe and induces an adequate immune response.