The two vaccines against Ebola tested in Liberia have a lasting effect on the organism of the volunteers. A year after the injection, they still have antibodies.
Quickly done, well done. The vaccines against Ebola, developed in emergency at the time of the epidemic in West Africa, have a good safety profile. According to a large study conducted in Liberia in 2014, few side effects were reported within a year of injection. Good news reported in the New England Journal of Medicine.
The clinical trial in question, PREVAIL, was conducted at the heart of the Ebola epidemic. 1,500 adults were recruited by American-Liberian teams. They were separated into three groups: those who received a placebo, and those who tested two candidate vaccines (cAd3-EBOZ and rVSV-ZEBOV).
Sustainable efficiency
It takes some time for volunteers to develop a response to the vaccine, which is characterized by the production of antibodies. This does not appear until after a month. At this period of the study, 71% and 84% of participants exposed to candidate vaccines presented a satisfactory reaction. This phenomenon is marginal in the group treated with placebo.
One year after the experience, the benefits of the gesture are still present. Two-thirds of participants who received cAd3-EBOZ still have antibodies. In the group that was exposed to rVSV-ZEBOV, the same observation applies to eight out of ten volunteers.
The presence of antibodies among the members of the placebo group is surprising. In fact, at the start of the study, 4% of participants already had them. As the researchers point out, this is a sign that an Ebola virus infection has occurred, but has not caused symptoms.
An example
In terms of security, the record is impeccable. Less than one in ten volunteers complained of severe side effects. In most cases (71%), malaria was the cause of the symptoms. This parasitic disease is endemic in this region of West Africa. Symptoms at the injection site are classic – as are the moderate side effects: headache, muscle pain, fever, and fatigue.
In a statement, the director of the National Institute of Infectious Diseases and Allergies (NIAID) welcomes these positive results. “This clinical trial (…) demonstrates that an ethical and well-designed research project can be carried out during an epidemic,” enthuses Anthony Fauci.
In fact, the experiment bore fruit and was replicated later. During the Zika epidemic in Latin America, researchers closely followed the patients and advanced on treatment avenues.
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