Ebola: Did experimental drug used on British patients stop them developing the virus?

London’s Royal Free Hospital used the Japanese drug favipiravir

A nurse preparing facilities for a potential Ebola patient at the Royal Free Hospital in north London, last year (Getty Images)

A drug used to treat British healthcare workers who came into contact with Ebola-infected blood may have protected them from the disease, UK doctors have said, and has the potential to help contain any future outbreaks.

The celebrated treatment team at London’s Royal Free Hospital, who cared for three British Ebola patients – as well as several other healthcare workers suspected of having contracted the virus while working with patients in Sierra Leone – were the first in the world to use experimental antiviral treatments in an attempt to prevent the onset of the disease.

Now, in a report of their work in The Lancet medical journal, the team have revealed that two healthcare workers whose skin was accidentally pricked with needles contaminated with fresh, Ebola-infected blood, did not go on to develop the disease, after being treated with the Japanese-developed drug favipiravir.

While it cannot be known whether the two had actually contracted Ebola, researchers said this was the first time such a high risk event had not resulted in an Ebola infection.

Two other healthcare workers, who also sustained accidental “needlestick injuries” while working in Ebola treatment centre “red zones” were also given the drug, and neither developed the disease. In one case the needle had not been used, and in another, it was not known whether the needle was infected or not.

Dr Michael Jacobs, the infectious disease specialist who leads the team at the Royal Free said that the findings merited further investigation.

West Africa’s Ebola outbreak – by far the worst the world has ever seen – led to an unprecedented acceleration in research into possible vaccines and treatments. A vaccine has proven 100 per cent effective in recent trials in Guinea, but the evidence around potential treatments – which would still be required in the event of a future outbreak – is less conclusive.

Favipiravir works as a post-exposure prophylaxis (PEP) – a drug used in an attempt to prevent a virus taking hold after a possible infection.

“We are excited to publish the first report of an antiviral-based post-exposure treatment against Ebola-virus infection in humans,” said Dr Jacobs. “We believe this works justifies further study of this post-exposure treatment to protect healthcare workers accidentally exposed to Ebola virus in the field.

“What is more, a similar approach to treat household contacts of Ebola cases may work to prevent a major route of spread during an epidemic.”

Dr Jacobs added: “Of course we can’t draw firm conclusions from such a small number of patients, but it’s exciting because, in previous descriptions of people who have acquired Ebola through the use of medical devices like this, they have all acquired disease and most have died.

“All of this is superseded if the vaccine is really effective but it’s almost impossible to envisage a situation where Ebola would arrive and you would have an entirely vaccinated population. You need both – they are complementary strategies.”

British Ebola survivor William Pooley was exposed to the disease while working with patients in Sierra Leone

The two British patients who came into contact with infected blood were also treated with experimental monoclonal antibody drugs – similar to the widely publicised ZMapp, which was identified early in the outbreak as a potential treatment.

In West Africa, Ebola has infected nearly 28,000 and killed more than 11,000 people since the outbreak began in December 2013. At its peak in-between autumn and winter last year, hundreds of new cases were being confirmed every week across Guinea, Sierra Leone and Liberia, leading to a major international military aid operation to support the country’s healthcare systems, including the deployment of UK military health personnel and NHS volunteers.

The number of new cases has since declined dramatically, with only three identified in West Africa in the week to 19th August, all of them in Guinea. In Sierra Leone, no-one is currently being treated for Ebola; the first time this has been the case for more than a year. However, the country must remain without a case for 42 days to be declared Ebola-free.