Promising developments in the fight against Ebola

The recent outbreak of Ebola in West Africa has triggered fast-paced research towards the development of a potential vaccine. Recent results published online in the New England Journal of Medicine suggest that one might just have been successfully developed.

Electron micrograph of an Ebola virus virion (credit: Centre for Disease Control and Prevention, Wikipedia)

Electron micrograph of an Ebola virus virion (credit: Centre for Disease Control and Prevention, Wikipedia)

In August 2014, the World Health Organization declared the epidemic of Ebola virus disease (EVD) to be an international public health emergency. It was the first time that such a declaration had been made since the first discovery of the disease in 1976. While more than 20 outbreaks have been recorded in the last forty years, the current one has struck for its violence with already more cases officially reported – 15,000 cases and 5,420 deaths – than all prior EVD outbreaks combined. Fortunately, the quest to develop a vaccine to bring the epidemic to an end and prevent future large outbreaks seems now at arm’s reach.

An experimental Ebola vaccine has been recently co-developed by the US National Institute of Allergy and Infection Diseases and the British multinational healthcare company GlaxoSmithKline. Tested at the National Institute of Health Clinical Center in Bethesda, Maryland, the first results are extremely encouraging. The vaccine contains segments of Ebola virus genetic material from two species of the virus – Sudan and Zaire. The Ebola genetic material is packed in and delivered by a carrier virus (chimpanzee-derived adenovirus 3) which causes a common cold in chimpanzees but is harmless to humans. The candidate vaccine does not contain an active Ebola virus and, as such, cannot give rise to the disease, however it triggers – at least that was the hope of the researchers – the production of anti-Ebola antibodies.

The candidate vaccine was given in a Phase 1 clinical trial to twenty volunteers between 18 and 50 years of age – ten received a lower dose of the vaccine and ten a higher one. After two and four weeks following vaccination the subjects’ blood was tested and all twenty showed presence of anti-Ebola antibodies within four weeks, with higher levels in the volunteers who received the higher dosage. The vaccine also prompted the production of CD8 T cells in two subjects who received the lower dose and in seven of those who received the higher dose. This is relevant as a previous study showed that non-human primates inoculated with the same vaccine developed both the antibodies and the T cells and this was enough to protect them from contracting the disease despite being exposed to lethally high levels of Ebola Virus. None of the twenty volunteers tested showed serious adverse effects, although two of those who received the higher dosage developed a briefly lasting fever within a day from vaccination.

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Carlo Bradac

Carlo Bradac

Dr Carlo Bradac is a Research Fellow at the University of Technology, Sydney (UTS). He studied physics and engineering at the Polytechnic of Milan (Italy) where he achieved his Bachelor of Science (2004) and Master of Science (2006) in Engineering for Physics and Mathematics. During his employment experience, he worked as Application Engineer and Process Automation & Control Engineer. In 2012 he completed his PhD in Physics at Macquarie University, Sydney (Australia). He worked as a Postdoctoral Research Fellow at Sydney University and Macquarie University, before moving to UTS upon receiving the Chancellor Postdoctoral Research and DECRA Fellowships.

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