Scimex: Based on promising data from initial clinical trials in late 2014,
WHO with the Health Ministry of Guinea, Médecins Sans Frontières (MSF),
Epicentre and The Norwegian Institute of Public Health (NIPH), will
launch a Phase III trial in Guinea on 7 March to test the VSV-EBOV
vaccine for efficacy and effectiveness to prevent Ebola. The vaccine was
developed by the Public Health Agency of Canada. A second vaccine will
be tested in a sequential study, as supply becomes available.
"We
have worked hard to reach this point," said WHO Director-General, Dr
Margaret Chan. "There has been massive mobilization on the part of the
affected countries and all partners to accelerate the development and
availability of proven interventions. If a vaccine is found effective,
it will be the first preventive tool against Ebola in history."
Vaccination
will take place in areas of Basse Guinée, the region that currently has
the highest number of cases in the country. The trial strategy adopted
will be "ring vaccination", based on the approach used to eradicate
smallpox in the 1970s. This involves the identification of a newly
diagnosed Ebola case – the "index case" – and the tracing of all his/her
contacts. The contacts are vaccinated if they give their consent.
"The
Ebola epidemic shows signs of receding but we cannot let down our guard
until we reach zero cases," said Assistant Director-General Marie-Paule
Kieny, who leads the Ebola Research and Development effort at WHO. "An
effective vaccine to control current flare-ups could be the game-changer
to finally end this epidemic and an insurance policy for any future
ones."
The objectives of the trial are two-fold: to assess if the
vaccine protects the contacts who were vaccinated and if vaccinating the
contacts will create a buffer - or ring of protected individuals -
around the index case to prevent further spread of the infection.
Vaccination will also be proposed to frontline workers in the area where
the trial will take place.
Canadian governmental institutions are
supporting the trial through the provision of critical training and
support to the African research teams conducting the trial, in addition
to scientific advice.
In the last six months WHO has convened a
series of emergency consultations with scientists, ethicists, regulators
and policy makers to identify potential preventive and therapeutic
products to help stem the epidemic. Canada's VSV and GSK cAd3 vaccines
quickly emerged as promising tools due to prior successful studies on
non-human primates.
"For more than a year we have been racing around the clock to stop the
epidemic from spreading further," explains Bertrand Draguez, Medical
Director at MSF.
"We need to ensure that we continue our efforts
to identify infection cases and follow up on their contacts, and in
parallel keep promoting R&D for treatments, diagnostics and
vaccines. This epidemic remains unpredictable. We don't know when it
will end, and that's why it remains crucial for us to keep focusing our
efforts on developing a vaccine capable of protecting the population in
this epidemic and any future ones. Frontline workers and the contacts of
infected patients will be enrolled, if they consent, in the vaccine
study."
"Participation of the community in the study areas in
Guinea is vital to enable the successful assessment of this vaccine,"
stresses John-Arne Røttingen, NIPH, and chair of the study steering
group. "The study process has ensured the inclusion of Guinean
investigators since its inception, and is a response to a request from
Guinean authorities."
Since September 2014, the two most advanced
Ebola vaccines have been evaluated in about 15 countries in Africa,
Europe and North America. The testing timelines were considerably
accelerated through the simultaneous organization of multiple trials and
emergency procedures to expedite data sharing and analysis between the
investigators and manufacturers. The VSV-EBOV vaccine was selected for
the planned trial based on a framework of parameters developed by the
WHO Scientific and Technical Advisory Committee on Ebola Experimental
interventions (STAC-EE). Criteria included acceptable safety profile,
induction of appropriate immune responses, including neutralizing
antibodies, and the timely availability of sufficient supplies of
vaccine doses.
Further measures were taken to accelerate the
testing process by organizing multi-country emergency assessments, joint
ethical and regulatory reviews of trial protocols and clearing of
regulatory hurdles. For the Guinea trial, the Guinea National Regulatory
Authority with support from Health Canada jointly reviewed the trial
protocol.
WHO, UNICEF, US Centers for Disease Control (CDC), the
Bill and Melinda Gates Foundation and GAVI (the Global Vaccine Alliance)
are collaborating with the affected countries to develop plans and
strategies for large-scale introduction, should this be needed. The
vaccines' manufacturers have assured that enough vaccine will be
available in the coming months. Financial resources are in place to
procure and make vaccines available to the Ebola affected countries.
Million of doses will be funded by GAVI, whose Executive Board approved a
US$ 300 million funding envelope in December 2014. There are also U$ 90
million earmarked to support the deployment of the vaccine(s).