‘Ebola Vaccines Prove Safe for 600 Trial Participants’



The Co-Principal Investigator of Partnership for Research on Ebola Vaccines in Liberia (PREVAIL), Dr. Fatorma Bolay, has disclosed that Ebola vaccines have proven safe for 600 participants in phase two of the study in Liberia.

He said there are plans now to shift to Phase Three with a new study of Ebola survivors.

Speaking Tuesday at the Ministry of Information regular press briefing on Capitol Hill in Monrovia, Dr. Bolay explained that PREVAIL has achieved and exceeded its initial goal of enrolling 600 people in its Phase Two component.

When an independent monitoring group recently reviewed the interim study data on the first 600 people enrolled, it found no major safety concerns related to either of the two study vaccines, said Dr. Bolay.

According to him, the Data and Safety Monitoring Board (DSMB) commended the team’s accomplishment and said the information collected on the safety of the vaccines support the goal of advancing to the larger phase.

The Phase Two portion of the study enrolled at least 600 people who were followed closely to find out whether the vaccines were safe and whether they could elicit an immune response before proceeding to Phase Three of the vaccine trials in Liberia, explained Dr. Bolay.

“The enrollment in PREVAIL has been steady after intensive engagement with home community of volunteers. As the protocol specifies, after reaching 600, the study has to continue to enroll participants,” Dr. Bolay indicated.

According to him, Phase Three component of the vaccines study is planned to enroll about 27,000 Liberians at risk of infections. 

“Achieving a marked decline in new Ebola cases approaching zero is a wonderful achievement for the people of Liberia and the country.  However, with so few Ebola infections occurring in Liberia, the Phase Three study here at this point would be unable scientifically to put the efficacy of the vaccines to a rigorous litmus test,” he noted.

Dr. Bolay explained that the Liberia-U.S. Research team is evaluating the best way to move forward to contribute to Ebola-directed scientific efforts in West Africa; in addition to exploring the possibility of co-sharing the Phase Three PREVAIL with other countries in the West African sub-region.

According to him, at least two additional blood samples would be obtained from all participants at 6 and 12 months post-vaccination to determine the durability of the immune responses but said the process is being reviewed by the U. S. Food and Drug Administration.  

“We thank the Liberia-U.S. Clinical Research team conducting this study for their excellent work, as well as the many hundreds of Liberians who stepped up to participate and contribute to this clinical milestone,” noted Dr. Francis N. Kateh, Deputy Manager for Medical Affairs and Planning at Liberia’s Incident Management System (IMS).


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