CDC begins Ebola vaccine trial in Sierra Leone

More than 6,000 volunteers in Sierra Leone are being vaccinated for Ebola as part of a long-awaited clinical trial, which U.S. health officials say they hope can help stem the outbreak.

The Centers for Disease Control and Prevention (CDC) has partnered with local health officials and disease researchers in Sierra Leone to launch the trial, which will include 6,000 healthcare workers on the frontlines of the disease.

Health officials said the new clinical trial will be a lengthy process and could last beyond the current epidemic, acknowledging it might play a greater role in preventing future cases. It is the first clinical trial to begin in West Africa.

"We don't know whether this vaccine will be the Ebola prevention tool we're all eager for, but we hope that what we learn from STRIVE will help us save lives during this and future Ebola outbreaks," Dr. Anne Schuchat, director of CDC's National Center for Immunization and Respiratory Diseases, wrote in a statement.

Participants will either receive the vaccine immediately upon enrolling in the trial or within six months. Each person will be encouraged to remain vigilant in protecting themselves against Ebola while treating patients, because “it is not yet clear how much protection, if any,” the potential vaccine might offer.

CDC Director Dr. Tom Frieden, who has said a vaccine might be the only way to completely end the current Ebola outbreak, stressed that a vaccine "would be a very important tool to stop Ebola in the future."

"We hope this vaccine will be proven effective but in the meantime we must continue doing everything necessary to stop this epidemic -find every case, isolate and treat, safely and respectfully bury the dead, and find every single contact," he wrote.

More than 25,000 people have been infected with Ebola in West Africa and nearly 11,000 have died, according to the latest data from the World Health Organization.