Illustrations
Figure 1
Principle of the ring vaccination trial. A person showing clinical signs of Ebola with biological confirmation is an index case. People identified as being in direct contact (“contact”) with the index case such as family members and indirectly via a direct contact such as neighbours (“contact of contact”) are enrolled in the vaccination trial; see [4] for details.
Figure 1
Figure 2
Genome organization of Ebola virus (EBOV), vesicular stomatitis virus (VSV) and recombinant chimeric VSV-ZEBOVGP in which the gene coding for the VSV surface glycoprotein has been replaced by the surface glycoprotein GP from Zaire EBOV strain. Note that VSV-ZEBOVGP produces viral particles enveloped by the EBOVGP; consequently, VSV-ZEBOVGP exhibits the cell host range of EBOV [6] .
Figure 2
Figure 3
Convergent observations made in vaccination trials with VSV-ZEBOVGP done in non-human primates (A) and humans (B) according to vaccination trial in macaques against the 2014-2015 Ebola virus outbreak strain1 , the ring vaccination trial in Guinea2 , and the phase I trial in humans3 . A) VSV-ZEBOVGP partially protects macaques against EBOV challenge done only three days after vaccination and protects all individual challenged with EBOV at 7, 14, 21 or 21 days post-vaccination1 . The type I interferon (IFNα) response and VSV-ZEBOVGP viremia were measured in blood drew every three days for nine days then every week1 . Note that in the group challenged on day 3, EBOVGP specific antibodies were already detectable three days after the challenge (green dotted line) while antibodies were below the detection threshold in the other groups challenged later (green line). B) The “at risk of Ebola” and “protected from Ebola” periods reflect the actual observations in the ring vaccination trials in the group of contacts and contacts of contacts having received immediate vaccination2 . In the phase I trial, EBOLA specific antibodies (green star) were determined only at 28 days post-vaccination3 . Note the reported observation times lasted about 40-45 days post-vaccination.
1 data from [14] . 2 data from [1] . 3 data from [7] .
Figure 3
Auteur
CIRI, Inserm U1111, CNRS UMR5308, Université Claude-Bernard Lyon 1, ENS de Lyon, 21, avenue Tony-Garnier, 69007 Lyon, France
The promising ability of a recombinant vaccine to protect humans against the risk of getting infected upon contact with Ebola-sick patients comes as one of the best news from the recent devastating Ebola crisis in Western Africa [1]. This trial is built according to the ring vaccination scheme that was used in the final stage of the smallpox eradication scheme [2] (figure 1). This scheme was developed to curtail the limitations of mass vaccination and to reduce exposure to the risk of severe side [...]