Liberia released its last Ebola patient on Thursday, and the World Health Organization (WHO) said the country has gone a full week with no new cases.
Beatrice Yardolo, 58, was admitted to a Chinese-run treatment in the capital, Monrovia, on Feb. 18, and said she was "one of the happiest persons on earth today" upon being discharged.
According to USA Today, the country can be declared Ebola free if it goes 42 days without any new infections.
Nearly 10,000 people have died of Ebola since it broke out across Liberia, Guinea, and Sierra Leone in December 2013. The disease has at times been carried to other countries — including the U.S. — however widespread outbreaks have not resulted in these places. In the week leading up to March 1, Guinea and Sierra Leone reported 132 new cases.
"We look at the three countries as really a single country, so while it's good news that Liberia itself has no new cases, the populations are so mobile in that region that there could easily be re-importations of cases," said WHO spokesman Gregory Hartl,
according to BBC News.
"We have to get down to zero in all three countries before we can consider this thing beaten."
Margaret Chan, the organization's director-general, said an Ebola vaccine trial will begin in Guinea on March 7.
"If a vaccine is found effective, it will be the first preventive tool against Ebola in history," she explained.