The vaccine, VSV-EBOV, developed
by the Public Health Agency of Canada, is highly effective against Ebola, shows
the results of an interim analysis of the Guinea Phase III efficacy vaccine
The trial is being conducted by
the Guinean authorities, the World Health Organization (WHO), Medecins Sans
Frontieres (MSF), and the Norwegian Institute of Public Health, with support
from a strong group of international and national organizations.
The Data and Safety Monitoring
Board (DSMB), an independent group of experts who monitor treatment efficacy
data during a clinical trial, had conducted the analysis and advised that the
trial should continue.
The analyses and views from the DSMB
were published in the journal The Lancet
Dr. Margaret Chan,
Director-General of the World Health Organization, said that the world is on
the verge of getting a effective Ebola vaccine
development is exceptionally promising.
"The credit goes to the Guinean
Government, the people living in the communities and our partners in this
project. An effective vaccine will be another very important tool for both
current and future Ebola outbreaks," Dr. Chan said.
Dr. Chan also - notably - said
that the vaccine upto now shows 100% efficacy in trials, but more proof is
required to ensure its capacity to protect populations through herd immunity.
Draguez, MSF Medical Director, said that the current data basically means that
the vaccine works to protect people against the Ebola virus.
if the sample size is quite small and more research and analysis is needed, the
enormity of the public health emergency should lead us to continue using this
vaccine right now to protect those who might get exposed to the disease,
contacts of infected patients and frontline workers," Draguez said.
the Ebola virus
affected countries to start using
this vaccine as soon as they can within the framework of the existing trial.
that we know that the vaccine works, people who need it most should
imperatively get it as soon as possible to break the existing chains of
transmission. Replication of a targeted approach focusing on those most at risk
of infection should therefore happen immediately and we urge governments in
affected countries to start using this vaccine as soon as they can within the
framework of the existing trial," Draguez added.
The Ebola Vaccine Trial
The 'ring' vaccination method
adopted for the vaccine trial was designed an expert group from the WHO, in association
with developed countries including Canada, France, Guinea, the United Kingdom,
the United States of America, Norway, and Switzerland.
Professor Donald A. Henderson of
John Hopkins University, who led the WHO's exclusive smallpox eradication program
by using the ring vaccination strategy is one of the noted figures in the
John-Arne Rottingen, Director of
the Division of Infectious Disease Control at the Norwegian Institute of Public
Health and Chair of the Study Steering Group, said that the Guinean Ebola trial
is also based on the smallpox eradication strategy.
"The concept of the ring
vaccination method is simple. We can create a protective shield, which is the so called
ring, to stop the virus from spreading further by vaccinating all people in
contact with an Ebola-infected person. This method has helped us to follow the
dispersed epidemic in Guinea in disease control strategy. The ring vaccination
method will help to carry on the trial as a public health intervention," Rottingen
According to international
sources, the Guinea vaccination trial began on 23 March 2015. The trial aims to
examine the efficacy and safety of a single dose of the VSV-EBOV with the ring
vaccination strategy. About 4000 people working close with around 100 Ebola
patients have voluntarily participated in the trial.
In order to ensure people at high
risk receiving the vaccine immediately, the trial stopped randomization on 26
July. The step was also intended to minimize the time necessary to gather more
conclusive evidence necessary for eventual licensure of the vaccine. About 50%
of the rings were separately vaccinated three weeks after the identification of
an infected patient. This measure is expected to provide a term of comparison
with rings that were vaccinated three weeks after the identification and
vaccinated immediately. Taking into account of the current analysis, the
authorities have decided to include 13 to 17-year-old and possibly 6 to
12-year-old children in the trial.
MSF authorities said that a
separate trial of the same vaccine on frontline workers is also being
"These frontline workers have
worked tirelessly to take care of sick people. They risked their lives to take
care of sick people every day. As the vaccine is responding well and effective,
then we are already saving them from possible infection. We think, it is the
right time for all affected countries to start ring vaccination programs to
break the chains of transmission. Countries should also conduct vaccination for
frontline workers." an MSF authority said.
Dr. Sakoba Keita, Guinea's
national coordinator for the Ebola response, said that they have worked really
hard to develop a effective vaccine for Ebola and the VSV-EBOV vaccine is
Guinea's gift to West Africa and the world.
"The thousands of volunteers
including Guinean doctors, data managers and community mobilizers have
contributed to pull up this initial success of the ground breaking trial," Dr.
Jeremy Farrar, Director of the Wellcome
Trust, who provide financial assistance to the trial said that this is a
remarkable achievement which shows the power of international partnerships.
"This success on the win over
Ebola shows that such an effective and critical work is not impossible in the
midst of a terrible disease outbreak or epidemic. This is how the world should
respond to such emerging disease threats. Wellcome Trust and all our partners,
is fully committed to giving the world an effective vaccine," Farrar said.
Marie-Paule Kieny, Assistant
Director-General, who leads the Ebola Research at the WHO said that this
record-breaking work marks a turning point and the end of the Ebola will be
"The urgency of saving
lives can accelerate research and development. We will use this experience
harnessed from this Ebola program to develop a global research and development
preparedness framework. The framework will help the world to act quickly and
efficiently to develop and use medical tools and prevent a large-scale tragedy
if a major disease outbreak occurs in the future." Kieny said.