Antiviral-based therapies may have the potential to protect humans from the deadly Ebola virus, according to a report published in The Lancet Infectious Diseases. 

The report describes a case-series of eight British health-care workers who were evacuated to the Royal Free Hospital in London, UK after possible accidental exposure to Ebola virus in Sierra Leone between January and March 2015.

Four of the health-care workers were considered to have been at significant risk of exposure to Ebola from needlestick injuries and were given post-exposure prophylaxis (PEP) with the antiviral drug favipiravir (Toyama Chemical Company, with or without monoclonal antibodies (similar to ZMapp). The other four workers had exposure that was not the result of a sharps injury, and were judged to be at lower risk. They were not given PEP, but were managed by watchful waiting.

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None of the health-care workers went on to develop Ebola, according to the report. All eight healthcare workers remained healthy throughout the 42 day follow-up, with no signs of disease or detectable levels of virus in their blood. The treatment regimen was well tolerated with no serious adverse events reported.

“It is possible that none of these health-care workers were infected with Ebola virus. Therefore, we cannot know for sure whether or not post-exposure prophylaxis prevented the onset of Ebola-virus disease,” lead author Michael Jacobs from the Royal Free NHS Foundation Trust, London, said in a press release. “However, two of the workers had needlestick injuries contaminated with fresh blood from patients with Ebola virus disease putting them at very high risk of transmission.”

The risk of Ebola infection for healthcare workers in West Africa is high. By August, 5 2015, 880 out of 27,862 cases of Ebola were reported in healthcare workers. Yet, for doctors and nurses caring for Ebola patients there are no guidelines to quantify exposure risk, and until now, any evidence that PEP may be beneficial in humans.

The authors conclude by calling for standardized guidelines about transmission risk and management after potential exposure to be urgently developed and adopted as they have been for many other infections such as HIV and hepatitis B virus.


1. Jacobs M, et al.  Lancet Infect Dis. 2015; DOI: