Sierra Leone, one of the countries worst-hit by the Ebola virus, announced Friday that it would implement a four-day lockdown, to contain the disease in the West African nation. The move comes as the death toll from the outbreak reached over 2,000 people, and nearly 4,000 more have been infected since last December.

Under the lockdown conditions, citizens of Sierra Leone will not be allowed to leave their houses between Sept. 18 and Sept. 21, to allow the health workers identify more cases in the early stages of the disease. Ebola becomes contagious only after the incubation period of the first 2 to 21 days. More than 21,000 people have been hired to implement the lockdown in the country, Reuters reported. Sierra Leone has seen a 100 percent increase in the number new cases identified in the past 21 days.

"The aggressive approach is necessary to deal with the spread of Ebola once and for all," Ibrahim Ben Kargbo, a presidential adviser for Sierra Leone’s Ebola task force, told Reuters.

Last month, Liberia announced a lockdown in a large slum in Monrovia for almost a week, in an attempt to contain the disease.

Meanwhile, the World Health Organization, or WHO, announced on Friday that two new vaccines could be made available to the health workers by November, as they remain the most at risk of contracting the disease. Since March, more than 20 health workers have died due to the ebola virus in Sierra Leone, according to a BBC report.

On Friday, WHO officials met for the second day in Geneva to discuss more therapies and vaccines to counter the worst-ever outbreak of the Ebola virus.

“The number of cases is rising exponentially,” Ban Ki-moon, the U.N. Secretary General said, according to the New York Times, adding: “The disease is spreading far faster than the response. People are increasingly frustrated that it is not being controlled.”

The WHO had recently estimated that it would cost nearly $600 million to fight the disease, while USAID is expected to spend about $75 million to expand the healthcare conditions in the Ebola care centers in Liberia.