A phase 3 clinical trial was launched on March 7, 2015 to test the VZV-ZEBOV vaccine. The tests take place in the region of the Lower Guinea where is the greatest number of patientsEbola.
Two vaccines being tested
The VZV-ZEBOV vaccine, developed by the Public Health Agency of Canada, and currently produced by Merck Laboratories, is one of the two vaccines currently most advanced in development.
The second, ChAd3, also designed by Canada, has been tested in phase 2 on 120 volunteers in Lausanne (Switzerland) since November 2014. The trial is nearing completion and additional tests will be conducted in West Africa.
Ebola vaccine: the belt strategy
The strategy adopted for the tests on the VZV-ZEBOV vaccine is that of the “belt”. This approach consists of identifying a new diagnosed case (or patient zero) and then vaccinating all the people who have been in contact with him.
Three weeks later, other potential contacts will be vaccinated.
The test vaccination will continue for three months and will be followed by a five-month observation. This technique was already used in the 1970s to eradicate smallpox.
Not everyone is affected by the trial
“In part of the trial, we are targeting workers who are on the front lines of the fight against Ebola. In another part, we will target people who have been in contact with confirmed cases and the contacts of these contacts”, specifies the World Health Organization (WHO). Under 18s and pregnant women are excluded from the test.
This trial phase has undesirable effects. The vaccinated person may experience fatigue, muscle pain, headache, fever and chills. These symptoms occur 24 hours after vaccination, according to the WHO. The effects are only temporary and have no lasting consequences.
Objective: to block the spread of the Ebola virus
“The affected countries and all partners have mobilized massively to accelerate the development and availability of effective medical interventions against this infection. If a vaccine is found to be effective, it will be a great first in the prevention of the virus. Ebola,” said Dr Margaret Chan, Director General of WHO.
This clinical trial will assess whether the vaccine protects the first circle of patient zero, including healthcare professionals, and whether vaccination creates a protective belt (or buffer zone) around the patient that would block the spread of infection.
“The Ebola virus disease outbreak shows signs of retreat but we cannot let our guard down until we have eliminated all the cases,” said Dr Marie-Paule Kieny, WHO Assistant Director General.
Read also :
– Ebola: the virus is mutating
– Infographic: everything you need to know about the Ebola virus
