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An experimental Ebola vaccine appears to safely protect people against infection and without causing feared side-effects such as arthritis, researchers reported Wednesday.
The vaccine, which has already been shipped to West Africa for more testing, uses an animal virus called vesicular stomatitis virus (VSV) to carry tiny pieces of the Ebola virus to help train the immune system to recognize it.
“The most common side effects were injection site pain and transient fever that appeared and resolved within 12 to 36 hours after vaccination,” the National Institute for Allergy and Infectious Diseases, which helped test the vaccine, said in a statement.
“We saw a robust immune response following a single dose of the vaccine."
Ebola’s infected more than 25,000 people in Sierra Leone, Guinea and Liberia and killed half or more of them, with 10,000 deaths confirmed. Research on vaccines and treatments for Ebola had been stalled for a lack of funding but picked up when the epidemic began to spread out of control.
This vaccine was tested in 40 volunteers at NIAID, part of the National Institutes of Health, and the nearby Walter Reed Army Institute of Research.
Within two weeks, 93 percent of them developed antibodies against Ebola virus, and everybody did within a month, the researchers report in the New England Journal of Medicine.
The vaccine uses a “live” VSV virus, and 30 percent of the volunteers had mild or moderate fever. The researchers said it wasn’t unexpected. In an earlier trial of the vaccine in Switzerland some volunteers complained of arthritis-like pain but no one in this trial did.
“We saw a robust immune response following a single dose of the vaccine, which could be particularly useful in outbreak interventions,” said Walter Reed’s Col. Stephen Thomas, who helped lead the study.
It's also possible the vaccine might help protect people exposed to the virus but not yet infected.
Several vaccine trials are under way in or planned for Liberia, Sierra Leone and Guinea and researchers are also testing drugs and blood products such as plasma to see if they help patients recover from the highly lethal virus.
"Until a safe and effective vaccine is available, the world will continue to be under-prepared for the next Ebola outbreak.”
While the epidemic is slowing, it’s important to have vaccines ready, said Dr. Anthony Fauci, who heads NIAID.
“The ongoing Ebola outbreak in West Africa is unprecedented in scope and duration,” Fauci said in a statement.
“The outbreak is slowly coming under control, thanks to extraordinary and multi-faceted efforts in the affected nations. However, there still are no licensed specific therapies or vaccines for Ebola. Until a safe and effective vaccine is available, the world will continue to be under-prepared for the next Ebola outbreak.”