EBOVAC1 implemented and completed three Phase 1 clinical trials in the UK, Kenya, and Uganda/Tanzania, in which a total of 231 adults were enrolled. A staged Phase 2b clinical trial in Sierra Leone – known as EBOVAC-Salone – began in 2015, and the last participant visit was completed in July 2019. A total of 1,019 participants were enrolled into this study, comprising 443 adults, 192 adolescents aged 12-17, 192 children aged 4-11 and 192 children aged 1-3. This study was the first study to include toddler-age children following a successful age-de-escalation and review by an external safety monitoring board.
An additional Phase 2 study in Sierra Leone – known as SL PREVAC – to evaluate the safety and immunogenicity of three experimental Ebola vaccination strategies was also implemented by the EBOVAC1 team. A total of 708 participants were enrolled into the SL PREVAC study, comprising 397 adults, 145 adolescents aged 12-17, 117 children aged 5-11 and 49 children aged 1-4. The last participant visit in this study was completed in November 2019. SL PREVAC forms part of a larger study, with funding from NIAID, covering Guinea, Liberia and Mali.
Data from the EBOVAC1 studies overall indicate that the vaccine regimen is well tolerated and produces a strong and durable immune response in both adult and paediatric populations.
The Phase 1 trial results from the UK study (EBL1001) were published in JAMA: The Journal of the American Medical Association in April 2016 (
http://dx.doi.org/10.1001/jama.2016.4218(öffnet in neuem Fenster)). The two-dose vaccination regimen was well-tolerated and immunogenic (produced an immune response). Final data from the same study published in JAMA in March 2017 (
http://dx.doi.org/10.1001/jama.2016.20644(öffnet in neuem Fenster)) showed that the immune response persisted in volunteers for at least 1 year after vaccination.
The results from the Phase 1 trials in Kenya (EBL1003) and Uganda/Tanzania (EBL1004) were published in the Journal of Infectious Diseases in February 2019 (
https://doi.org/10.1093/infdis/jiy625(öffnet in neuem Fenster) and
https://doi.org/10.1093/infdis/jiz070(öffnet in neuem Fenster)). In both studies, the data show that the vaccine regimen was well tolerated and highly immunogenic.
Data from the Phase 3 study in Sierra Leone (EBL3001) were presented in two articles published in September 2021 in the Lancet Infectious Diseases (
https://doi.org/10.1016/(öffnet in neuem Fenster) S1473-3099(21)00125-0 and
https://doi.org/10.1016/(öffnet in neuem Fenster) S1473-3099(21)00128-6). These data confirmed the findings of previous studies, again demonstrating that the vaccine regimen was well tolerated and produced durable immune responses in adults and children.