Ebola vaccine trial underway in Sierra Leone

A clinical trial coordinated by the London School of Hygiene & Tropical Medicine to assess the safety and immunogenicity of a new vaccine against Ebola started this week in Kambia District, north-western Sierra Leone.

The first volunteers in the EBOVAC-Salone study were vaccinated at the clinic in Kambia Town on Thursday 8 October, and more volunteers from the district will be enrolled in stages over the course of the next few months.

The trial is being run by a team of doctors and scientists led by led Dr Bailah Leigh at Sierra Leone's College of Medicine and Allied Health Sciences with Dr Deborah Watson-Jones and Professor Sir Brian Greenwood at the School under the EBOVAC1 project.

The EBOVAC1 consortium brings together leading global research institutions and non-government organisations including the London School of Hygiene & Tropical Medicine, the Janssen Pharmaceutical Companies of Johnson & Johnson, Inserm, the University of Oxford, World Vision, Grameen Foundation and GOAL, as well as Sierra Leone's Ministry of Health and Sanitation. These partners are working with support from the European Union's Innovative Medicines Initiative Ebola+ programme.

The 'prime-boost' vaccine being studied in EBOVAC-Salone is different to other vaccines currently being tested in the region. The vaccines being studied are Ad26.ZEBOV and MVA-BN-Filo, developed by Crucell Holland B.V., one of the Janssen Pharmaceutical Companies, and Bavarian Nordic.

Volunteers in the study are first given the 'prime' dose to prepare the immune system to defend itself against the virus if it comes into contact with Ebola. Two months later volunteers receive the 'boost' dose in order to increase the immune response, with the goal of potentially strengthening and optimizing the duration of immunity to the Ebola virus.

Professor Peter Piot, Director of the London School of Hygiene & Tropical Medicine, said: "We cannot afford to be complacent about Ebola. We urgently need a vaccine that offers long term protection of the population, including health workers and other care givers, in order to prevent a resurgence of the virus.

"To achieve this goal, it is vital to test a range of vaccine candidates, particularly in the areas affected by the epidemic where we are still seeing new cases emerging, and there is evidence that the infection may have longer-term effects among survivors. Prime-boost vaccination is an effective strategy for long-term prevention of several infectious diseases, and we believe it may have a key role to play in the fight against Ebola."

Developing effective vaccines against Ebola is a global public health priority. To date, there is no licensed vaccine, treatment or cure for the Ebola virus, so new ways to stop people becoming infected with Ebola are urgently needed.   It is crucial to study a number of different vaccines in different populations and circumstances so that there is more than one tested and licensed vaccine available to prevent against future outbreaks of the Ebola virus.

The Janssen vaccines, which are currently being tested in clinical studies in the United States, the United Kingdom, Kenya, Uganda and Tanzania, have already been given to several hundred people to date with no serious adverse events reported.  Studies are also planned for other European and African countries, but it is vital to study the effects on people in areas such as Kambia, at the centre of the recent epidemic.

Dr Bailah Leigh, Principal Investigator of the study, said: "I am proud to be leading a team of Sierra Leonean doctors and nurses, working in partnership with our international colleagues, to study this new vaccine regimen against Ebola. I hope that our work on this EBOVAC-Salone study will help to save lives both here in Sierra Leone and beyond.

"Ebola has devastated lives and communities across Sierra Leone and our neighbouring countries. Now that the epidemic is waning we must focus our efforts on preventing this happening ever again. Developing successful vaccines against this terrible disease is crucial if we are to fight Ebola in the future"

Significant investment has been made by the study partners to build new facilities in Kambia, strengthening the local health system.  These include the first Emergency Room at the Kambia District Hospital, and a new vaccine storage facility on the hospital site. The team has recruited and trained doctors, nurses and other frontline healthcare workers who will gain valuable experience while contributing to the clinical study.