With more than 21,000 people infected and close to 9,000 dead, the Ebola outbreak in West Africa is the worst yet involving the virus. Scientists are a step closer, though, to finding a cure, with a clinical trial starting in Liberia Monday.

The clinical trial was launched in Monrovia, Liberia's capital, with performers singing songs explaining the trial's purpose. Joseph Nyumah Boakai, the country's vice president, addressed residents in the city, saying the vaccines being tested are not just important for Liberia but the rest of the world as well.

Conspiracy theories against the vaccines have taken a life of their own, but Boakai tried his hardest to pacify Liberians, urging the people to have courage because the trial is going to work.

Smaller studies have shown that the Ebola vaccines being developed are indeed safe for use by humans. Up to 600 volunteers will be participating in the first phase of the trial, eventually ballooning to 27,000 as the trial progresses, according to organizers.

Two experimental vaccines will be used in the clinical trial. Dr. Anthony Fauci, U.S. National Institute of Allergy and Infectious Diseases director, explained that both have showed a lot of promise in safety tests so they were chosen for use in the clinical trials. One of the vaccines was developed by the National Institutes of Health (to be produced by GlaxoSmithKline) while the other one was developed by health officials in Canada and licensed to Merck and NewLink Genetics.

B. Emmanuel Lansana was the first volunteer to receive the Ebola vaccines Monday. Two shots were administered to him, placed at different points along his right arm. A physician's assistant, Lansana wanted to participate in the trial despite his wife's apprehensions. He decided to go through with volunteering completely when his concerns were clarified during counseling prior to receiving the vaccines.

He was under observation 30 minutes after being administered the shots and appeared fine.

"Once injected into the body these genes encode Ebola proteins, not virus, but proteins that stimulate an immune response against the Ebola virus itself," explained Fauci of how the vaccines were designed to work.

The clinical trial comes at a time when for the first time since June 2014, fewer than 100 cases were reported in Guinea, Liberia and Sierra Leone for the past week. Without a vaccine, up until now health officials have fought the outbreak with public health measures that include isolating the sick, tracking and quarantining those who had contact with them, and setting up teams to safely bury bodies. Among the hardest hit have been health workers and those who cared for ill family members, as the highly contagious virus is spread by direct contact with bodily fluids of those infected.