By fear of the bioterrorism,
the United States tries out a vaccine against the Ebola virus
(Le Monde/THE WORLD | 21.11.03
)
The American medical
authorities have, Tuesday 18 November, announced the launching of the first
clinical trial aiming at studying the harmlessness and the effectiveness of
an experimental vaccine intended to prevent the infection by the hemorrhagic
fever of Ebola.
One does not have today any preventive or curative method against this
highly contagious affection and frequently mortal who prevails in a
recurring way in equatorial Africa.
The national Institutes of health American (NIH) specify that the first
phase of this clinical trial will relate to vingt-sept voluntary old from 18
to 44 years. Six of them will receive a placebo and twenty and the one
vaccine in the form of three injections distributed over one two months
period. These volunteers will be supervised m�dicalement during a year.
This clinical trial followed upon an experiment undertaken on monkeys by the
team of Doctor Gary Nabel, within the Research center on vaccines (VRC) of
the American national Institute of study of the allergies and infectious
diseases. Conduit during three years, this work made it possible to obtain a
total immunization of the vaccinated animals. "This test shows the capacity
of the VRC to be passed quickly from fundamental research to tangible
products", commented on Doctor Anthony Fauci (NIH).
The Ebola virus bears the name of an affluent of Congo close to the town of
Yambuku (Zaire) where, in 1976, it for the first time was identified, at the
time of an epidemic which touched 318 people and killed 280 out of them. It
acts of the one of the longest known viruses. It has the shape of a wire and
consists of a nucleic bit of acid inserted in a lipidic envelope.
The duration of incubation of the disease varies few days at three weeks.
The symptoms of this affection associate a fever, abdominal pains intense
and often hemorrhagic diarrhoeas accompanied by insufficiencies renal and
hepatic. During the epidemic, the Ebola virus is transmitted via direct
contacts with the biological fluids (blood, saliva, vomits, sperm, saddles)
of the infected people who, for this reason, must be quarantined as fast as
possible. In spite of the investigations led in various African countries,
in particular by the specialists in the Pasteur Institute of Paris, one does
not know the animal species which, lodging this virus without in being
affected, is at the origin of its emergence at the man.
"WEAPON OF DISSUASION"
Produced by the company of biotechnology Vical de San Diego (California),
the vaccine which starts to be tested in the United States consists of a
ad�novirus in the genome of which one inserted genes which direct the viral
protein synthesis. These last should start in the organization of the
vaccinated people the synthesis of antibody immunizing them against the
Ebola virus. This vaccine does not contain any structure directly derived
from the virus. Its use thus does not present, in theory, any danger.
"an effective vaccine against the fever of Ebola would not only make it
possible to protect the most exposed people in the countries where this
disease generally prevails in a natural way, explained Doctor Fauci. It
would constitute also a weapon of dissuasion with respect to those which
could plan to use this virus with fine bioterrorists." In addition to the
virus of variola and the bacillus of coal, the American specialists in the
fight against the bioterrorism have feared for several years the use which
could be made pathogenic agents responsible for the hemorrhagic fevers, and
particularly of the Ebola virus.
Jean-Yves Nau.
