2 Feb 2015

Will Ebola vaccine trial in Liberia be successful?

The world’s first large-scale Ebola vaccine trial gets underway in Liberia, as a second British military healthcare worker is flown back to the UK for monitoring after possible exposure to the virus.

The first large-scale trials of the experimental Ebola vaccine got underway on Monday in Monrovia – one of the worst-affected areas in Liberia. It is hoped that 30,000 people will now participate in the immunisation programme.

The vaccine was created by using a virus from a chimpanzee and was developed by GlaxoSmithKline (GSK) and the US National Institutes of Health.

Ebola vaccine trial

The vaccine is the first to arrive in one of the main Ebola-affected countries, and will be used to start the first large-scale efficacy trial of experimental Ebola vaccines in the coming weeks.

It is already being tested in five small phase-one clinical trials in Great Britain, the United States, Switzerland and Mali. Around 200 healthy volunteers were involved in the current test, according to GSK.

The World Health Organisation said the case incidence continues to fall in Guinea, Liberia, and Sierra Leone, which can make it harder to tell if any vaccine is effective.

Commenting on the possibility that the numbers of the potential Ebola candidates in Liberia is not big enough for a valid trial, Raanan Gillon, professor of medical ethics at Imperial College London, said it was “very important to aim to get significant results because it’s a terrible waste and, indeed, potential danger to give ineffective treatments and vaccines that actually don’t work and possibly may be harmful.”

Next-generation vaccines

As west Africa’s devastating Ebola outbreak begins to dwindle, scientists are looking beyond the endgame at the kind of next-generation vaccines needed for a vital stockpile to hit another epidemic hard and fast.

Determined not to lose scientific momentum that could make the world’s first effective Ebola interventions a reality, researchers say the shots, as well as being proven to work, must be cheap, easy to handle in Africa and able to hit multiple virus strains.

That may mean shifting focus from the stripped-down, fast-tracked vaccine development ideas that have dominated the past six months, but it mustn’t mean the field gets bogged down in complexities, experts say.

“We need a stockpile because there will be other outbreaks,” said Seth Berkley, chief executive of the GAVI global immunisation alliance, which helps bulk-buy vaccines for poor countries.

A second UK military healthcare worker has been flown back to England after "likely exposure" to the virus in Sierra Leone.

The healthcare worker arrived in the UK today and has been admitted to the Royal Free Hospital in London for an assessment.

It comes after another British military healthcare worker was flown back to England for monitoring after suffering a needle-stick injury, also in Sierra Leone.

They have not been diagnosed with Ebola and do not have symptoms, said Public Health England.

Officials stressed there is no risk to public health and said the two cases appear to be unrelated.

Professor Paul Cosford, Public Health England's (PHE) director for health protection, said: "We can confirm that all the appropriate support is being offered to this individual and that strict protocols have been followed to transfer them back to the UK.

"We would like to emphasise that there is no risk to the general public's health. Our thoughts are with both of the healthcare workers, and their families, affected at this time."